# Subwoofer Tests - Spring 2007



## Ilkka

If the weather permits, the next round of subwoofer testing will be held on the first weekend of *May, 5-6th* to be more exact. At this moment it looks like we will have enough subs to make it a two day event like last year. :surrender: 

I have been contacting many subwoofer companies (domestic and foreign) and also Finnish subwoofer importers during this spring, and the list below pretty much shows who replied positively. There were also some dropouts due close but no cigar date of publications. You can probably guess those subwoofers. Of course many of those subs are privately owned and thereby loaned by their owners. :hail: Do notice that this is still a preliminary list, I'm sure there will be some changes until the actual testing begins.

The testing methodology has been adjusted a bit, but the biggest change is the new CEA 2010 standard that will be accommodated. 

BK Monolith-DF (same unit was tested last time, will be used as a reference)
BK XLS200-DF
B&W PV1
Chorus Vertigo XLS 07
DIY Adire Audio Tumult 15" MK1 sealed 100L
DIY Peerless XLS 12" ported 85L
DIY Rythmik Audio Servo 12" sealed 56L
DIY Tangband W8-740E 8" sealed 9L
DIY TC-Sounds 2xTC-2000 15" sealed 140L
DIY TC-Sounds TC-2000 15" ported 270L
DIY TC-Sounds TC-2000 15" sealed 90L
HSU MBM-12
HSU VTF-3 MK3 + turbo
Monitor Audio BRW10 
SVS 20-39PC+ (12.3)
SVS PB12-NSD
SVS SB12-Plus
Velodyne SPL-1200 MK2

So called 'maybe list'. Meaning not confirmed yet or under consideration whether I am going to test it or not.

Pioneer S-W250S

I would definitely like to have some/more large and low tuned ported subs (LLT), but unfortunately many of them are being built as we speak and won't necessarily be ready before the testing begins. I also know that there are many Soundsplinter's 15" and 18" drivers on a ship somewhere on the Atlantic ocean... :duh:

I will update this post as I have new information about the event.


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## WillyD

I really hope that 270L TC-2000 sub can make it.


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## ssabripo

yo....if you pay for insurance and shipping, plus a dialy stipend for the number of days I would be without one of my towers, you are more than free to take one of them and put it in your shootout!


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## Ilkka

WillyD said:


> I really hope that 270L TC-2000 sub can make it.


Yes, that subwoofer is done (I've actually listened to it), and the guy lives pretty close to me. There are some small transportation problems but we WILL overcome them. :boxer:

I will definitely like to see that 90L sealed TC-2000 15" being compared to this large ported version. I have a feeling that I am not the only one...

There is also a ported ~500L RL-p 18" in the works. If the driver arrives in time, it will be there too.


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## Ilkka

ssabripo said:


> yo....if you pay for insurance and shipping, plus a dialy stipend for the number of days I would be without one of my towers, you are more than free to take one of them and put it in your shootout!


Oh can I? :sarcastic:


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## Blaser

Well, very exciting to see how the famous brands compare to the DIYs!!

Blaser


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## WillyD

> I will definitely like to see that 90L sealed TC-2000 15" being compared to this large ported version. I have a feeling that I am not the only one...


Oh wow, yeah, that would be fantastic. About as close as one could get to comparing the performance of good designs for both alignment using the same driver.


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## Egil

Im also looking forward to the results, since there is a lot of condenders in the lineup im curious about


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## Chrisbee

Will you be using a control subwoofer to check the stability of test conditions over the test period? I think Tom V suggested this.


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## Warpdrv

Chrisbee said:


> Will you be using a control subwoofer to check the stability of test conditions over the test period? I think Tom V suggested this.



BK Monolith-DF (same unit was tested last time, will be used as a reference)


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## Chrisbee

Warpdrv said:


> BK Monolith-DF (same unit was tested last time, will be used as a reference)


I imagine that would be popular choice in Europe since it is a known quantity. 

Assuming you retest and publish the Monolith graphs all the other subwoofers tested will be straight comparisons. :T 

A head to head between the PB12+ and the Monolith would settle a lot of discussion. :devil:


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## Sonnie

You can borrow my Behemoth if you'd like... :scratch: :huh:


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## Ilkka

Chrisbee said:


> Will you be using a control subwoofer to check the stability of test conditions over the test period? I think Tom V suggested this.


Yes, I will be using a reference subwoofer from the previous round so we can see how comparable those results are. I will also check the stability of the test conditions over the test period (meaning between each day).


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## Ilkka

Sonnie said:


> You can borrow my Behemoth if you'd like... :scratch: :huh:


If only we'd live a little bit closer to each other... :hissyfit:


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## Ilkka

WillyD said:


> I really hope that 270L TC-2000 sub can make it.


I'm happy to tell that it's confirmed. :bigsmile:

Also added Monitor Audio BRW10 and B&W PV1.


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## WillyD

Ilkka said:


> I'm happy to tell that it's confirmed. :bigsmile:


:jump:


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## Ilkka

Here's the picture of the LLT in its home.

- TC-2000 15"
- 270 L
- 16 Hz / 6" aeroport
- 2 kW


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## WillyD

Is it the SVC or DVC? If it is the DVC, wried in series or parallel? What amp is being used?


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## Ilkka

WillyD said:


> Is it the SVC or DVC? If it is the DVC, wried in series or parallel? What amp is being used?


It is SVC, so 4 ohm bridged.

The amp is a Novacoustic (Solton / Craaft Audio) X 2000 clone. Measured output of ~2 kW into 4 ohm bridged. My own sealed 2x15" sub will have two of these. :devil:

We are going to have two dedicated 16A/230V lines for these puppies. No line sag problems. :T 

http://www.novacoustic.com/html/x_amps.html


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## WillyD

Suuuhhhhhweeeeeeet. :bigsmile:


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## bossobass

Ilkka said:


> It is SVC, so 4 ohm bridged.
> 
> The amp is a Novacoustic (Solton / Craaft Audio) X 2000 clone. Measured output of ~2 kW into 4 ohm bridged. My own sealed 2x15" sub will have two of these. :devil:
> 
> We are going to have two dedicated 16A/230V lines for these puppies. No line sag problems. :T
> 
> http://www.novacoustic.com/html/x_amps.html


This is most excellent news. Leave it to Ilkka to hit the nail on the head:bigsmile: 

As you know, I've said for years that the perfect comparo fromn vented to sealed is to cut box size in 1/2, double the drivers and amplification.

Looks like we have the perfect comparo, but...will you apply differing L/T curves to the sealed sub, or just measure it natural?

It will actually be easy to determine the maximum flat output curve at various L/T'd F3 points from the maximum output curve of the natural 2X15" sealed sub, but it's easier to see the curves on one graph and it wouldn't allow for different L/T induced system Q graphs.

This is where the Bassis would make it a breeze to run tests of varying tune and Q combinations.

Either way, I'm glued to the screen. I'll probably be able to comment on your TC driven system vs various other drivers I've used.

Glad to hear that you've anticipated the need for current to the amplifiers.

Just excellent stuff. Can't wait:T 

Bosso


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## Blaser

WillyD said:


> :jump:


Let's see what this is capable of compared to the very known brands:R 

Blaser


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## Ilkka

bossobass said:


> Looks like we have the perfect comparo, but...will you apply differing L/T curves to the sealed sub, or just measure it natural?
> 
> It will actually be easy to determine the maximum flat output curve at various L/T'd F3 points from the maximum output curve of the natural 2X15" sealed sub, but it's easier to see the curves on one graph and it wouldn't allow for different L/T induced system Q graphs.


I will take two separate measurements: natural and ~12 dB L/T.


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## WillyD

So Ilkka, ready for the big day tomorrow? :bigsmile:


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## brandonnash

Weather looking good in your part of the world tomorrow? If it all goes well tomorrow, when do you think you'll be able to post some findings?


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## WillyD

I don't know where he lives in Finland, but the weather looks OK there.


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## Blaser

Let's all wish the best for the Great Ilkka tomorrow and the day after.... I think he may not post the results before 1 week or so:hissyfit: .... Up to now, avtalk did not post their result...


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## Ilkka

We are ready to begin! :jump: And luckily the weather is fine too. A little bit chilly, but as we already know, the subwoofers like it.

Can't say anything about the results yet. They are posted when they are done. You can't probably imagine how much manual work that requires... :dizzy:


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## WillyD

Good luck with the tests. I hope they are going well.


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## Ilkka

First day is happily behind us. The weather was fine and we got some nice results too. Here are a few teaser pics and strictly unofficial CEA 2010 standard max clean peak output results (subtract 3 dB for more common RMS values). NA means 'not available', which means that the subwoofer wasn't able to output considerable amounts of sound pressure at that frequency. You should notice that when comparing the average values.

The Velodyne SPL1200-MK2 couldn't make it due transportation problems. Maybe next time.


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## Kevin_Wadsworth

Thanks for the pics and unofficial results! Looks like a beautiful day there in Finland.

At least in terms of output, it looks like the DIY guys are more than holding there own.


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## jpmst3

Nice, keep up the good work!:bigsmile:


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## Ilkka

One interesting note. The large TC-2000 15" based sonosub was clipping its ~2000W amp at 40 Hz and above. :scared:


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## Blaser

The TC-2000 DIY sub is a freek!! 

Ilkka.... one word!! ::hail:


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## Blaser

I would like to thank you for posting this unofficial results, which only make us feel as if we were with you at the tests. You could have simply waited for a week or two and take your time before informing anything about what you have.... But understanding people are very impatient, you have taken the time to post something to help us be patient....

This is very highly appreciated Ilkka!! Not many guys do like you do.... know what I mean:whistling: 

I have 1 ton questions or 2:R , but will of course wait for the official results and leave you concentrate on what your doing now!!

Best wishes for tomorrow:T 

Blaser
Thanks!


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## ransac

Illka,
Have you ever considered running the powered subs in a passive mode and connect them to the same amp as you use for the other passive subs? By using the same power source with the same settings, you would then be comparing the drivers, enclosures, and alignments. It would also expose if the OEM has under powered the amp or over compensated the control circuits or limiters.


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## WillyD

Ilkka said:


> One interesting note. The large TC-2000 15" based sonosub was clipping its ~2000W amp at 40 Hz and above. :scared:


Those results look about dead on for the TC-2000 too, pretty much what one would expect. Fantastic. Thanks for giving us a little taste of what is to come. Keep up the good work man, we all really appreciate you spending your weekend doing this (your friends and those who donated a sub to test too!). :bigsmile:

And wow about the amp clipping!


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## Kevin_Wadsworth

ransac said:


> Illka,
> Have you ever considered running the powered subs in a passive mode and connect them to the same amp as you use for the other passive subs? By using the same power source with the same settings, you would then be comparing the drivers, enclosures, and alignments. It would also expose if the OEM has under powered the amp or over compensated the control circuits or limiters.


Aside form being a lot more work, I think many may find that less valuable. The point here isn't to compare drivers/enclosures, it is to compare subs.


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## Blaser

Very good post Kevin... And wellcome to the shack!!

Ransac, in addition to Kevin's point, I would ask you if for example you would like Ilkka to send 2000 Watts to a Pb-12 NSD??:scratch: If the answer is no, then how much would be acceptable?

When dealing with a DIY, we know what the driver can and cannot take not only speaking of power, but most importanly speaking of *Peak excursion*!!

How can you know for ex. the excursion limited frequencies of the NSD? Is it only below tuning? Not really! Where and how much power input will make it reach peak excursion above tuning...:dunno: . I can't be sure of that.

I think for these reasons it will not be possible/ meaningful...

Blaser


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## WillyD

Yeah, the way Ilkka does it now is really the only way (and the right way). Commercial sub buyers use the subs as is. The second you physically change the sub (voiding the warranty too) the tests become sort of pointless.


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## jmcomp124

I would love to see an 18" LMS-5400 in the list.
They are expected to be in stock in the next 3 weeks. 
Here is my first DIY adventure with an 18" LMS-5400 and Passive Radiators (most likely 2 or maybe 3) in a 7 to 10 cu ft (depending on number of PRs) box. Model results show about 118dB at 16Hz and 120dB at 20Hz. I will be building 2 of these subs :jump: 
-Jai


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## Blaser

After having been an owner of the DTS....(you jmcomp124 not me:R ) I can understand why you are building 2 of these monsters:devil: 

Blaser


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## Ilkka

Tomorrow's the time for these puppies. 

DIY Adire Audio Tumult 15" MK1 sealed 100L
DIY Rythmik Audio Servo 12" sealed 56L
DIY TC-Sounds 2xTC-2000 15" sealed 140L
DIY TC-Sounds TC-2000 15" sealed 90L
HSU VTF-3 MK3 + turbo (with and w/o turbo)
SVS 20-39PC+ (12.3) (20 Hz and 16 Hz tunes)

Let's see if we can beat today's numbers. :boxer:


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## Exocer

Ilkka nice work! Loving your work so far. Keep it up.

Particularly interested in the Tumult results.


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## jmcomp124

blaser said:


> After having been an owner of the DTS....(you jmcomp124 not me:R ) I can understand why you are building 2 of these monsters:devil:
> 
> Blaser


I hope it will cure my subwoofer illness raying: 

I hope someday Illkka will share his measuring secrets openly. By far, his are the most compreshensive and accurate available on the internet. I have communicated with him through PMs to help me learn some of this stuff for example the MaxSPL sweeps. He has a comprehensive "Tests Explained section" and how to use TrueRTA etc, but some critical stuff I need is missing. He uses SpectraPro and was not able to share specific information of the testing methodology. 

Maybe I should ship my subs to Finland or travel with them :spend: 
I am posting my thoughts here so Ilkka would reconsider sharing some of the testing methodology in more detail so it will be beneficial for a lot of folks.


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## Blaser

What is the *critical*stuff that you are needing and that is missing?:scratch: :waiting:


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## jmcomp124

blaser said:


> What is the *critical*stuff that you are needing and that is missing?:scratch: :waiting:


The setup for accurate MaxSPL sweep measurements with corresponding THD. I think that data will be invaluable for getting a reasonably good idea of what it would perform in real world. According to Illka those tests are not simple as they appear. He said he uses SpectraPro but more specific information on the setup is confidential and in my mind the critcal part that is missing. Over time, I think he has been perfecting his methodology and someone like me just beginning to do those has a lot to learn in the setup. One might end up getting some MaxSPL sweep measurements but they will not be accurate and needs to be done right. I am asking to relax the confidentiality . He may have good reasons for it though, which I don't understand/know.


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## Blaser

Ilkka said:


> One interesting note. The large TC-2000 15" based sonosub was clipping its ~2000W amp at 40 Hz and above. :scared:


I see also that the averange SPL did take into consideration 12.5 Hz, while IMO it shouldn't as no other subs did anything there, so it would be fair to ignore this value at 12.5 Hz.... this makes the average SPL 115.4 db  otherwise it will appear as if the other subs were performing "up high" relatively better than the TC 2000.


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## jmcomp124

blaser said:


> I see also that the averange SPL did take into consideration 12.5 Hz, while IMO it shouldn't as no other subs did anything there, so it would be fair to ignore this value at 12.5 Hz.... this makes the average SPL 115.4 db  otherwise it will appear as if the other subs were performing "up high" relatively better than the TC 2000.


I am thrilled to see so many DIY stuff here. Once an area I dared not tread, with immense support from avs, I am entering it now, still with caution.
I wonder what a large ported LMS 5400 do!
I am looking forward for all the results that are about to come up !!!


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## WillyD

You know, I almost forgot about this, but I'd have to believe that the TC-2000 vented sub is suffering from port compression down low. I knew this beforehand...but didn't really think about it again till now.

Mmm...


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## jmcomp124

blaser said:


> I see also that the averange SPL did take into consideration 12.5 Hz, while IMO it shouldn't as no other subs did anything there, so it would be fair to ignore this value at 12.5 Hz.... this makes the average SPL 115.4 db  otherwise it will appear as if the other subs were performing "up high" relatively better than the TC 2000.


I agree. The average can be misleading while comparing one sub to another especially when the standard deviation (variance) between data points is high and in this case even missing. To see the potency of a unit across a spectrum, some kind of weighted average (this could get tricky) with more weights to lower frequencies can be a useful metric.


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## jmcomp124

WillyD said:


> You know, I almost forgot about this, but I'd have to believe that the TC-2000 vented sub is suffering from port compression down low. I knew this beforehand...but didn't really think about it again till now.
> 
> Mmm...


WillyD,
You see the reason for my excitement about Passive Radiators.


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## WillyD

jmcomp124 said:


> WillyD,
> You see the reason for my excitement about Passive Radiators.


Oh indeed. There is zero way to use the LMS-5400 in a ported design with compression, unless one goes with passive radiators. 

I've thought about going with a horizontal sonosub with 15" active/18" passive unit myself...onder:


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## Manic Miner

Thanks for the numbers Illka  What really hit me is that the big OEMs are being left in the dust by the smaller companies, and that with the rapid product cycles that the smaller companies have that difference is just likely to increase


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## Blaser

WillyD said:


> Oh indeed. There is zero way to use the LMS-5400 in a ported design with compression, unless one goes with passive radiators.
> 
> I've thought about going with a horizontal sonosub with 15" active/18" passive unit myself...onder:


WHY HORIZONTAL?:scratch:


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## steve nn

Very interesting Ilkka. As you might surmise, this is definitely the most interesting Thread I have came across in a loooong time. I notice the tune of the TC-15 has been mentioned?.. OK tune it to 20-25 Hz and see how much more it has to give from 20 on up! mmm :shh: 

Anyway I'll really be looking forward to part two.. nice job Ilkka


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## Ryan-T

Blaser, Passives need to be run horizontal. Too much sag.


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## jmcomp124

Ryan-T said:


> Blaser, Passives need to be run horizontal. Too much sag.


Yes, and think of 2.5Kgs :holycow: at the lowest tuning point.


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## WillyD

blaser said:


> WHY HORIZONTAL?:scratch:


As others have mentioned, you need to run PRs perpendicular to the ground, (not facing up or down). However you want to say it..

And it would fit will in the room where my HT will go.


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## Blaser

Well, I admit I am not very good in PRs:R , but that seems logical! Is this because there is no motor?


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## Ilkka

The second day is a wrap. :dizzy: Unfortunately we weren't that lucky today, and we had to interrupt the tests because of rain. Therefore we couldn't measure the SVS 20-39PC+. If we have a nice weather on next weekend, we can probably measure it then. I couldn't also measure my own dual TC-2000 sub L/T'd, only natural response. I think I will also bring that along if we will measure the SVS cylinder.

Some of the results I measured today have been puzzling me for the whole evening. Mainly the "problem" are the two sealed TC-2000 15" based DIY subs. I have to contact TC-Sounds before publishing any new results. Hopefully you will understand. :waiting:

I DO have some pictures for you. :yes: 

Day 1 pics

Day 2 pics


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## jmcomp124

Ilkka said:


> The second day is a wrap. :dizzy: Unfortunately we weren't that lucky today, and we had to interrupt the tests because of rain. Therefore we couldn't measure the SVS 20-39PC+. If we have a nice weather on next weekend, we can probably measure it then. I couldn't also measure my own dual TC-2000 sub L/T'd, only natural response. I think I will also bring that along if we will measure the SVS cylinder.
> 
> Some of the results I measured today have been puzzling me for the whole evening. Mainly the "problem" are the two sealed TC-2000 15" based DIY subs. I have to contact TC-Sounds before publishing any new results. Hopefully you will understand. :waiting:
> 
> I DO have some pictures for you. :yes:
> 
> Day 1 pics
> 
> Day 2 pics


Thanks for the awesome pics!! That untimely rain is a bummer. Portland, OR is not much better :rant: 
Well, now you got me really curious about the TC-2000 since I am waiting on 18" LMS-5400s and 4-6 Passive radiators.
Youd don't have to tell us the results, but can you at least give us a hint on what happened? Good or bad?
lease:


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## Ed Mullen

jmcomp124 said:


> I hope it will cure my subwoofer illness raying:
> 
> I hope someday Illkka will share his measuring secrets openly. By far, his are the most compreshensive and accurate available on the internet. I have communicated with him through PMs to help me learn some of this stuff for example the MaxSPL sweeps. He has a comprehensive "Tests Explained section" and how to use TrueRTA etc, but some critical stuff I need is missing. He uses SpectraPro and was not able to share specific information of the testing methodology.
> 
> Maybe I should ship my subs to Finland or travel with them :spend:
> I am posting my thoughts here so Ilkka would reconsider sharing some of the testing methodology in more detail so it will be beneficial for a lot of folks.


Trust me Jai - you don't want to get into this stuff that heavily. You'll need S/T SpectraPro (have your priced this lately?), a pro-grade mic, a pro-grade SPL calibrator, a spot to test outdoors that is at least 70 feet from reflective structures, a powerful lap-top, a pro-grade sound card, and interconnects. 

Then you are facing a huge learning curve on how to set-up this software and use it properly and effectively. I know exactly why Ilkka is reluctant to openly share his test methodology with everyone - he has hundreds and hundreds of hours invested in learning how to measure subwoofers accurately and how to manipulate the software and the raw data to crunch the numbers and generate the graphs. He considers this information intellectual property with considerable inherent value.


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## Ilkka

jmcomp124 said:


> Youd don't have to tell us the results, but can you at least give us a hint on what happened? Good or bad?
> lease:


Sorry, not until I have discussed with TC-Sounds.

Naturally it's something strange/bad.


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## brandonnash

Ilkka said:


> Some of the results I measured today have been puzzling me for the whole evening. Mainly the "problem" are the two sealed TC-2000 15" based DIY subs. I have to contact TC-Sounds before publishing any new results. Hopefully you will understand. :waiting:


Understand completely. But with the performance of the vented TC diy, I don't think the manufacturer is going to mind that much. 

Great pics btw.


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## Ilkka

Here's the updated (and still unofficial) CEA 2010 standard max output spreadsheet. Today's results are on bottom of the list. I have excluded both of the sealed TC-2000 based subs and naturally also the SVS 20-39PC+ that we couldn't measure due to the rain.


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## jmcomp124

Ed Mullen said:


> Trust me Jai - you don't want to get into this stuff that heavily. You'll need S/T SpectraPro (have your priced this lately?), a pro-grade mic, a pro-grade SPL calibrator, a spot to test outdoors that is at least 70 feet from reflective structures, a powerful lap-top, a pro-grade sound card, and interconnects.
> 
> Then you are facing a huge learning curve on how to set-up this software and use it properly and effectively. I know exactly why Ilkka is reluctant to openly share his test methodology with everyone - he has hundreds and hundreds of hours invested in learning how to measure subwoofers accurately and how to manipulate the software and the raw data to crunch the numbers and generate the graphs. He considers this information intellectual property with considerable inherent value.


Hi Ed,
I believe you. Someday when I have a lot of free time, I am going to come back to you guys. Maybe on my sabbatical .


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## Ed Mullen

jmcomp124 said:


> Hi Ed,
> I believe you. Someday when I have a lot of free time, I am going to come back to you guys. Maybe on my sabbatical .


It takes a real masochist to stick with this stuff - you're making the right call. :yes:


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## jmcomp124

Ilkka said:


> Sorry, not until I have discussed with TC-Sounds.
> 
> Naturally it's something strange/bad.


Ok, no harm in me taking a guess. You did indicate in an earlier post that your 2000W amp was clipping in a very efficient ported box over 40Hz and that was a single woofer. 
Now you have 2 in a sealed box and it has become a greedy power hungry beast :cunning: 
If this is what the issue is, then it may not be too bad. You just need more amp. 
How are the duals wired (effective impedance?)?


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## Ilkka

jmcomp124 said:


> How are the duals wired (effective impedance?)?


Two 4 ohm SVC drivers, both amps bridged.


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## Exocer

Wow, that sealed Tumult did incredibly well (so far) beating out the ported HSU accross the board...


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## Ilkka

steve nn said:


> Very interesting Ilkka. As you might surmise, this is definitely the most interesting Thread I have came across in a loooong time. I notice the tune of the TC-15 has been mentioned?.. OK tune it to 20-25 Hz and see how much more it has to give from 20 on up! mmm :shh:
> 
> Anyway I'll really be looking forward to part two.. nice job Ilkka


Thanks br! 

The large vented sonosub was tuned to ~16 Hz (measured).


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## Blaser

Ilkka,

Very good effort appreciated from all of us. I think the dual TC 2000 sealed sub is very important to you, and at your place I wouldn't be very happy if I ever discovered any kind of problem during measurements:sad: .

I hope you will get the problem solved asap (if there is ever one)raying: .

Again, thanks for having taken the time to post us some results after your hard day.

Best wishes!


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## jmcomp124

Ilkka said:


> Two 4 ohm SVC drivers, both amps bridged.


Ilkka,
That is plenty of power. 
Whatever your problem is with the TC2K, I hope it gets resolved quickly and easily.
I am truly appreciative of all your efforts and amazing passion for what you do.
Take care and do keep us posted on the issue.
Regards,
-Jai


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## jmcomp124

Ilkka said:


> Two 4 ohm SVC drivers, both amps bridged.


Ilkka,
Also, are you using any EQ? If so, how many filters and at what Frequencies, Q and boost/dip?
I did a quick model in WinISD and I can see how quickly apparent ampifier loads is going off charts with EQ.


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## steve nn

> Wow, that sealed Tumult did incredibly well (so far) beating out the ported HSU accross the board...


Yeah! very impressive! Another thing that I notice is how the little PCi "that could" hangs in there pretty **** well.


> The large vented sonosub was tuned to ~16 Hz (measured).
> Today 4:48 PM


Yeah I figured by the size and numbers. I actually still have one left in the spare room collecting dust. Hope you get things figured out TC-2 wise and things work out next weekend? It'll be hard to wait, but I'm sure a good conversation will in-sue.


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## WillyD

jmcomp124 said:


> Ilkka,
> Also, are you using any EQ? If so, how many filters and at what Frequencies, Q and boost/dip?
> I did a quick model in WinISD and I can see how quickly apparent ampifier loads is going off charts with EQ.


He wasn't even able to test the dual TC-2K sealed with any EQ due to the rain, he was only able to test its natural response.


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## Mark Seaton

Hi Ilkka,

Congrats on surviving another round of testing. I fully appreciate how daunting such an endeavor can be. 

Just to confirm, are these CEA 2010 values normalized numbers to 1m, or are they 2m values?

I very much look forward to all the other measurements taken. :clap:


----------



## Guest

Looking at the data, I can't imagine that the numbers are anything but 2m values.

Great work in getting several DIY designs tested Ilkka! With more and more formal testing performed on these designs, the benefits of DIY design become very clear to everyone.

On a side note, most people here already know this, but the actual CEA 2010 standard will have a rating for low bass and ultra low bass. Low bass will be the average of max SPL at 40/50/63Hz, and ultra low bass will be the average of max SPL at 20/25/31.5Hz.

Ilkka, what type of distortion threshold did you use for 12.5Hz, 16Hz, and 80Hz?

On a final note, the results below 50Hz for the MBM-12 should probably be ignored, since the response intentionally rolls off quickly below 50Hz (it is designed to handle primarily from 50-100Hz, used in conjunction with a deep bass subwoofer to handle <50Hz).


----------



## Ilkka

Mark Seaton said:


> Hi Ilkka,
> 
> Congrats on surviving another round of testing. I fully appreciate how daunting such an endeavor can be.
> 
> Just to confirm, are these CEA 2010 values normalized numbers to 1m, or are they 2m values?
> 
> I very much look forward to all the other measurements taken. :clap:


Thank you Mark! I think you are one of the few people who can really understand how much work there is. :dumbcrazy:

Those values are 2m. I will normalize them to 1m when I post the final results. Do notice that the standard uses peak, not RMS values. Peak = 3 dB higher than RMS.


----------



## Ilkka

Peter Marcks said:


> On a side note, most people here already know this, but the actual CEA 2010 standard will have a rating for low bass and ultra low bass. Low bass will be the average of max SPL at 40/50/63Hz, and ultra low bass will be the average of max SPL at 20/25/31.5Hz.


Yes, that is true. I just wanted to take some extra measurements when I had the chance. The final CEA 2010 scores will be calculated strictly according to the standard.



> Ilkka, what type of distortion threshold did you use for 12.5Hz, 16Hz, and 80Hz?


Same as for every other frequency. The standard does allow this.


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## Ilkka

WillyD said:


> He wasn't even able to test the dual TC-2K sealed with any EQ due to the rain, he was only able to test its natural response.


That's correct.


----------



## Ilkka

Here's the updated spreadsheet. Now I've also included the CEA 2010 standard 'Ultra low-bass' and 'Low-bass' scores.

All values still normalized to 2 m distance. Add 6 dB for 1 meter values.


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## crackyflipside

Very cool to see allot of DIY designs pitted head-to-head in real scientific (and quite thorough) tests. :clap: 

I can't wait to read through all the other pretty graphs!


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## jmcomp124

Ilkka said:


> Here's the updated spreadsheet. Now I've also included the CEA 2010 standard 'Ultra low-bass' and 'Low-bass' scores.
> 
> All values still normalized to 2 m distance. Add 6 dB for 1 meter values.


For the price and not being DIY, I am "very" impressed with what HSU and SVS have delivered with the MK3 and NSD. Kudos to you folks :clap:


----------



## Mark Seaton

Ilkka said:


> Thank you Mark! I think you are one of the few people who can really understand how much work there is. :dumbcrazy:
> 
> Those values are 2m. I will normalize them to 1m when I post the final results. Do notice that the standard uses peak, not RMS values. Peak = 3 dB higher than RMS.


Your welcome Ilkka. I had assumed it was 2m, but just wanted to clarify. I think your notation that you added above is plenty. The 2m values will be more useful in relation to the rest of your testing and data. Just a thought that came to mind. It could be useful to post a thread on the control sub which I recall was the BK Monolith. It would be interesting to maybe overlay the increasing output curves and distortion curves from each day to keep any variances between tests in perspective.

That's one big pile of data. I'm glad you have the honor of sorting and displaying it all and not me.  

Best Regards,


----------



## jmcomp124

Mark Seaton said:


> Your welcome Ilkka. I had assumed it was 2m, but just wanted to clarify. I think your notation that you added above is plenty. The 2m values will be more useful in relation to the rest of your testing and data. Just a thought that came to mind. It could be useful to post a thread on the control sub which I recall was the BK Monolith. It would be interesting to maybe overlay the increasing output curves and distortion curves from each day to keep any variances between tests in perspective.
> 
> That's one big pile of data. I'm glad you have the honor of sorting and displaying it all and not me.
> 
> Best Regards,


Mark,
Is the Submersive and the BMF going to Finland anytime soon? The BMF appears to be one amazing engineering work from the master of bass :T.

Ed,
How about the new Ultras? I've been longing to see those measurments. 


If not for my DIY project, I can see myself easily going for the new Ultras or the BMF. In fact, I was pretty close to buying the new Ultras as Ed knows. 

You have not forever lost me to DIY because what you folks come up with is so incredibly good and always full of surprises. 

Thanks,
-Jai


----------



## Guest

Outstanding comparison Illka. :T  Many congratulations for all the painstaking time and effort required to measure SPL and TH+N at all those frequencies for each sub. You're leading the way in using the CEA 2010 standard and I hope manufacturers sit up and take notice. Test studies like this should inspire companies to start quoting the Ultra low bass and Low bass statistics as part of their specification summaries rather than simply post raw SPL data without regard to how much of it is noise related. 

One additional comparative set of data which you have and would be useful, would be to post which order of HD is limiting output. It would help bridge the gap with other comparisons which tend to emphasize "sound quality". Also could you clarify how you generated the 1/3 octave band limited tone bursts at each test frequency? I recall a discussion some time ago about using an alternate technique.


----------



## Ed Mullen

jakeman said:


> Outstanding comparison Illka. :T  Many congratulations for all the painstaking time and effort required to measure SPL and TH+N at all those frequencies for each sub. You're leading the way in using the CEA 2010 standard and I hope manufacturers sit up and take notice. Test studies like this should inspire companies to start quoting the Ultra low bass and Low bass statistics as part of their specification summaries rather than simply post raw SPL data without regard to how much of it is noise related.
> 
> One additional comparative set of data which you have and would be useful, would be to post which order of HD is limiting output. It would help bridge the gap with other comparisons which tend to emphasize "sound quality". Also could you clarify how you generated the 1/3 octave band limited tone bursts at each test frequency? I recall a discussion some time ago about using an alternate technique.


There is a small universe of beta testers for the CEA 2010 program. 

Anyone using the program and attempting to reconcile their data against Ilkka's on the same subwoofer should be aware we both independently discovered an absolute SPL error in the software for which Ilkka has corrected/compensated in his results.

The program generates the tone bursts, and the spacing interval. It shows the limiting harmonic(s) and the % distortion for each and the THD at failure onset. So the data exists, the premliminary table just doesn't show it. Unless there is a problem with the subwoofer/driver, most will cap-out for orders 2-4.


----------



## Ed Mullen

jmcomp124 said:


> Ed,
> How about the new Ultras? I've been longing to see those measurments.
> 
> Thanks,
> -Jai


We'll likely be getting a PB13-Ultra into Ilkka's hands for his September shoot-out through L-Sound, our exclusive international distributor for the Scandinavia/Germany/Austria/Switzerland region.


----------



## Guest

Ed Mullen said:


> There is a small universe of beta testers for the CEA 2010 program.
> 
> Anyone using the program and attempting to reconcile their data against Ilkka's on the same subwoofer should be aware we both independently discovered an absolute SPL error in the software for which Ilkka has corrected/compensated in his results.
> 
> The program generates the tone bursts, and the spacing interval. It shows the limiting harmonic(s) and the % distortion for each and the THD at failure onset. So the data exists, the premliminary table just doesn't show it. Unless there is a problem with the subwoofer/driver, most will cap-out for orders 2-4.


Good to know, thanks Ed. Doesn't the CEA 2010 standard require you to calculate the maximum sound pressure before any of the weighted harmonics are exceeded? There may not be much difference between your and Illka's technique compared to the CEA guidelines but it would be helpful to know what was done differently and why? Other testers or in-house staff mayl try to replicate this data and it would be better to provide more detail now and avoid misunderstandings later. These CEA-2010 comparisons represent great progress in measuring subs. :clap: 

With regards to the test information itself, though most subs will max out from low order harmonics it would be great to know the ones if any that get limited by more offensive higher order or odd order harmonics. I remember reading your final Secrets poduct review of the Klipsch RT-12D and being very impressed at your finding "at the 40 Hz test frequency, the RT-12d generated a disproportionately high amount of upper order (7th-13th) distortion harmonics, which were audible during the testing. This behavior could not be duplicated at any other test frequency. Maximum output at 40 Hz was both electronically limited and capped by the CEA limits for the 12th and 13th order distortion harmonics." A more detailed explanation of harmonic behaviour by Illka would further enhance the quality of this set of tests. Its data like this which readers will find particularly useful because it is more relevant to sound quality and overall performance.


----------



## Ed Mullen

jakeman said:


> Good to know, thanks Ed. Doesn't the CEA 2010 standard require you to calculate the maximum sound pressure before any of the weighted harmonics are exceeded? There may not be much difference between your and Illka's technique compared to the CEA guidelines but it would be helpful to know what was done differently and why? Other testers or in-house staff mayl try to replicate this data and it would be better to provide more detail now and avoid misunderstandings later. These CEA-2010 comparisons represent great progress in measuring subs. :clap:
> 
> With regards to the test information itself, though most subs will max out from low order harmonics it would be great to know the ones if any that get limited by more offensive higher order or odd order harmonics. I remember reading your final Secrets poduct review of the Klipsch RT-12D and being very impressed at your finding "at the 40 Hz test frequency, the RT-12d generated a disproportionately high amount of upper order (7th-13th) distortion harmonics, which were audible during the testing. This behavior could not be duplicated at any other test frequency. Maximum output at 40 Hz was both electronically limited and capped by the CEA limits for the 12th and 13th order distortion harmonics." A more detailed explanation of harmonic behaviour by Illka would further enhance the quality of this set of tests. Its data like this which readers will find particularly useful because it is more relevant to sound quality and overall performance.


The program runs continuously and provides real-time feedback on the harmonic spectra and peak SPL and the pass/fail status. Basically the subwoofer is pushed to the point of failure and then the tester backs off the gain a hair until it passes and then records the peak SPL the subwoofer is able to generate just prior to failure. 

We're using the same program, but I just wanted others (who may also be using it) to know that there is still an absolute SPL error in the current beta version which needs to be corrected and that the data is not directly comparable to Ilkka's unless the correction is made. 

I have no doubt Ilkka will describe in at least some detail the failure onset conditions for each subwoofer. At a minimum listing the offending harmonic(s) would seem reasonable and not require much time.


----------



## Guest

Thanks for all the hard work Ilkka. I am VERY impressed with the performance of the Tumult MK1. Its really a shame that the Adire drivers are not available anymore.

-Eli


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## Guest

Ilkka said:


> Here's the updated spreadsheet. Now I've also included the CEA 2010 standard 'Ultra low-bass' and 'Low-bass' scores.
> 
> All values still normalized to 2 m distance. Add 6 dB for 1 meter values.





Peter Marcks said:


> On a final note, the results below 50Hz for the MBM-12 should probably be ignored, since the response intentionally rolls off quickly below 50Hz (it is designed to handle primarily from 50-100Hz, used in conjunction with a deep bass subwoofer to handle <50Hz).


To expand on my response above about the MBM-12, I should also mention that the deep bass subwoofer used with MBM-12 contributes equally at 50Hz. So the capability of the MBM-12 at 50Hz should be about +6db higher than what the testing data shows (ie. mutual coupling of the deep bass subwoofer and mid-bass module at 50Hz would lead to 6db more output).

Also, when using a deep bass subwoofer to handle low/mid/upper bass, the mid/upper bass would generally be limited by the low bass demands on the system. Testing for maximum output using harmonic distortion limits at various frequencies would not take this into account, since harmonic distortion is always some multiple of the test tone frequency. A deep bass subwoofer used with MBM-12 would have a mid/upper bass that is no longer limited by the low bass demands on the system.

Finally, the MBM-12 is designed to be placed in the nearfield, right next to the primary listening position(s). A deep bass subwoofer (handling low/mid/upper bass) positioned for best deep bass response would normally be placed much farther from the listening position. The closer distance to the listener means lower distortion for a given input level.

Of all the subwoofers tested during this session, only one came within 1db of the MBM-12's max output in the 50-80Hz range, and that was being driven by a 2000w RMS amp and expensive large woofer! So I am definitely happy about the performance of the 350w RMS module.


----------



## jmcomp124

Peter Marcks said:


> To expand on my response above about the MBM-12, I should also mention that the deep bass subwoofer used with MBM-12 contributes equally at 50Hz. So the capability of the MBM-12 at 50Hz should be about +6db higher than what the testing data shows (ie. mutual coupling of the deep bass subwoofer and mid-bass module at 50Hz would lead to 6db more output).
> 
> Also, when using a deep bass subwoofer to handle low/mid/upper bass, the mid/upper bass would generally be limited by the low bass demands on the system. Testing for maximum output using harmonic distortion limits at various frequencies would not take this into account, since harmonic distortion is always some multiple of the test tone frequency. A deep bass subwoofer used with MBM-12 would have a mid/upper bass that is no longer limited by the low bass demands on the system.


Peter,
Isn't the MBM designed to handle from 50 upto 150Hz?
Ilkka,
It appears that the MBM's headroom shows an increasing trend to 80Hz and probably beyond. Do you have the data points upto 150Hz for the MBM?
120dB from 50Hz to 150Hz would be very impressive and can compliment even very good mains that simply cannot deliver that much SPL.
Thanks,
-Jai


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## Guest

Jai, yes, the MBM-12 can handle that range. However, if using a crossover point higher than 80 or 90Hz, then it would have to be positioned up front near the main channel speakers as opposed to nearfield (due to increased directionality of the higher frequencies).


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## Ilkka

jmcomp124 said:


> Peter,
> Isn't the MBM designed to handle from 50 upto 150Hz?
> Ilkka,
> It appears that the MBM's headroom shows an increasing trend to 80Hz and probably beyond. Do you have the data points upto 150Hz for the MBM?
> 120dB from 50Hz to 150Hz would be very impressive and can compliment even very good mains that simply cannot deliver that much SPL.
> Thanks,
> -Jai


Yes I have. It did 116.3 dB @ 100 Hz and 113.8 dB @ 125 Hz.


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## jmcomp124

Peter Marcks said:


> Jai, yes, the MBM-12 can handle that range. However, if using a crossover point higher than 80 or 90Hz, then it would have to be positioned up front near the main channel speakers as opposed to nearfield (due to increased directionality of the higher frequencies).


Yes, that is exactly what I am thinking.
Thanks,
-Jai


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## jmcomp124

Ilkka said:


> Yes I have. It did 116.3 dB @ 100 Hz and 113.8 dB @ 125 Hz.


How about 150Hz?


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## steve nn

> For the price and not being DIY, I am "very" impressed with what HSU and SVS have delivered with the MK3 and NSD. Kudos to you folks


I couldn't agree more. Since a 15" driver only costs a little more than a 12", a guy might as well go the 15" rout unless real-estate or the $10-50 more is a deal breaker? 12" for 12" a guy might as well buy the SVS ore HSU unless he considers the build and the challenge half the attraction... or, unless he doesnt have to factor the amp because that's a done deal from past projects.

Thinking out-loud here Ed (good to see yuh!) From having had personal experience with all the current/past Ultra offerings "some dual" including three of the 300 L sono's, my guesstimate would put the new Ultra pretty **** close to the 270 TC-2000 sono!..mmmaybe a little beyond in a smaller package? Granted the Ultra would cost more, but Stout does come to mind along with DIY not being for the general HT enthusiast. Very impressive!


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## Ilkka

Ed Mullen said:


> I have no doubt Ilkka will describe in at least some detail the failure onset conditions for each subwoofer. At a minimum listing the offending harmonic(s) would seem reasonable and not require much time.


Yes, I will include at least that info when I post the final results.

Until that here are a few CEA 2010 spectras to explain this new test. During the weekend I saw all sorts of amplifier/driver behavior. Some were already limiting way before the standard allows, some produced mainly 2nd and 3rd order harmonics, while some were capped by the 9th and 10th or even higher harmonics.

1st example shows the spectra when the amp limits the output at much lower distortion level that the standard would allow.










2nd example shows the output being capped by the 2nd and 3rd order harmonics.










3rd example shows the output being capped by the 6th and 7th order harmonics.


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## Ilkka

jmcomp124 said:


> How about 150Hz?


I didn't test it. Probably less than at 125 Hz.

IMO that's not important info since one can not use a 150 Hz crossover with a single subwoofer. Anything beyond ~80-100 Hz is generally too high.


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## brucek

Ilkka,

So what do you use to supply your AC power out in the middle of a parking lot that can satisfy a 2000 watt amplifier without sagging? 

brucek


----------



## Ilkka

brucek said:


> Ilkka,
> 
> So what do you use to supply your AC power out in the middle of a parking lot that can satisfy a 2000 watt amplifier without sagging?
> 
> brucek


We had two dedicated 16A 230V lines. 40 meter cable length using heavy duty cable. There is a 40A 400V electric panel right next to the lot we used.


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## Ilkka

Mark Seaton said:


> It could be useful to post a thread on the control sub which I recall was the BK Monolith. It would be interesting to maybe overlay the increasing output curves and distortion curves from each day to keep any variances between tests in perspective.


I will definitely show those graphs when I post the full results. 



> That's one big pile of data. I'm glad you have the honor of sorting and displaying it all and not me.


Hah. :sarcastic: BTW, have you already posted the NYC pro shootout data?


----------



## jmcomp124

Ilkka said:


> Hah. :sarcastic: BTW, have you already posted the NYC pro shootout data?


It was a compliment from Mark, I believe. Most of us don't have the patience you do :rolleyesno:


----------



## Guest

Ilkka said:


> Yes, I will include at least that info when I post the final results.
> 
> Until that here are a few CEA 2010 spectras to explain this new test. During the weekend I saw all sorts of amplifier/driver behavior. Some were already limiting way before the standard allows, some produced mainly 2nd and 3rd order harmonics, while some were capped by the 9th and 10th or even higher harmonics.


The third graph would indicate unpleasant harmonics which would likely be audible in a comparative listening test. That part of the data set is perhaps more indicative of how these subs will perform sound quality wise than the raw SPL output measurements which most posters like to quote. I look forward to your writeup and more disclosure of those harmonics. 

If there are SPL errors in the current software beta version and that the resultant data is not directly comparable without a correction, may I suggest disclosing your correction factors. Because CEA-2010 testing is still in its early stages doing so will improve the veracity of your findings as some people/manufacturers may find the final measurements not to their liking.


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## Kevin_Wadsworth

Peter Marcks said:


> Of all the subwoofers tested during this session, only one came within 1db of the MBM-12's max output in the 50-80Hz range, and that was being driven by a 2000w RMS amp and expensive large woofer! So I am definitely happy about the performance of the 350w RMS module.


As you should be happy - the MBM does exactly what it is supposed to do and appears to do it well. On the other hand, though, the other subwoofer manufacturers/DIYers are probably happy that they do not have to double the cost of their setup by adding a second subwoofer to handle <50 dB bass.


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## Guest

Kevin_Wadsworth said:


> As you should be happy - the MBM does exactly what it is supposed to do and appears to do it well. On the other hand, though, the other subwoofer manufacturers/DIYers are probably happy that they do not have to double the cost of their setup by adding a second subwoofer to handle <50 dB bass.


Ah, but being cost-effective is exactly where the MBM-12 excels. Being able to use a relatively small and simple box, a light cone 12" low excursion woofer, and a relatively small amplifier helps to keep costs low. We sell the MBM to Hsu customers for a discount, so after shipping it ends up to be less than half the cost of a VTF-3 HO, and an even smaller fraction of the cost of something like dual VTF-3 Mk3. DIYers should be able to build it for even less money, and certainly for a small fraction of the cost it takes to build a very powerful deep bass subwoofer.


----------



## mike c

so, the Velodyne SPL still didn't make it to the second day?:bigsmile:


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## Ilkka

jmcomp124 said:


> It was a compliment from Mark, I believe. Most of us don't have the patience you do :rolleyesno:


Yes, I got it.


----------



## Ilkka

jakeman said:


> The third graph would indicate unpleasant harmonics which would likely be audible in a comparative listening test. That part of the data set is perhaps more indicative of how these subs will perform sound quality wise than the raw SPL output measurements which most posters like to quote. I look forward to your writeup and more disclosure of those harmonics.
> 
> If there are SPL errors in the current software beta version and that the resultant data is not directly comparable without a correction, may I suggest disclosing your correction factors. Because CEA-2010 testing is still in its early stages doing so will improve the veracity of your findings as some people/manufacturers may find the final measurements not to their liking.


Do notice that those upper harmonics only show up when the subwoofer is pushed to its limits. Things go much more even when you keep them "well" under their max output levels.

Yes, there is a 6 dB error (it reads too high) in the current software. My numbers are already corrected but someone else using the program should note it. We are working on finding out what can cause this error.


----------



## Ilkka

mike c said:


> so, the Velodyne SPL still didn't make it to the second day?:bigsmile:


Unfortunately not.


----------



## Mark Seaton

jakeman said:


> The third graph would indicate unpleasant harmonics which would likely be audible in a comparative listening test. That part of the data set is perhaps more indicative of how these subs will perform sound quality wise than the raw SPL output measurements which most posters like to quote. I look forward to your writeup and more disclosure of those harmonics.


Parallel to Ilkka's response above, I'd caution against going on a witch hunt for higher order harmonics.  Basically what you will see is the character/spectral change as the subs are notably overdriven at various frequencies. The ones with predominantly lower order harmonics will probably work a little better when budget and/or space dictate that they will be used in insufficient quantity to meet the listening levels of the user. The subs that eventually exhibit higher order distortion will more clearly "let you know" when you've pushed them too far. Arguements could be made for both cases. The first example above leaves the listener blissfully ignorant of the limiting other than the bass will no longer get louder and it will compress. Blissful ignorance still leaves the listener in bliss, and I think the behavior can definitely be preferred over other overload conditions, especially in more budget concious offerings.

The important thing to realize is that some frequency overloading with higher order harmonics doesn't mean it can't be very well behaved at levels below that threshold.


----------



## Ed Mullen

Mark Seaton said:


> Parallel to Ilkka's response above, I'd caution against going on a witch hunt for higher order harmonics.  Basically what you will see is the character/spectral change as the subs are notably overdriven at various frequencies. The ones with predominantly lower order harmonics will probably work a little better when budget and/or space dictate that they will be used in insufficient quantity to meet the listening levels of the user. The subs that eventually exhibit higher order distortion will more clearly "let you know" when you've pushed them too far. Arguements could be made for both cases. The first example above leaves the listener blissfully ignorant of the limiting other than the bass will no longer get louder and it will compress. Blissful ignorance still leaves the listener in bliss, and I think the behavior can definitely be preferred over other overload conditions, especially in more budget concious offerings.
> 
> The important thing to realize is that some frequency overloading with higher order harmonics doesn't mean it can't be very well behaved at levels below that threshold.


Of course this speaks to the whole clean headroom issue. If you have enough subwoofer for the given application, you don't have to worry about things like port noise, woofer overload, output compression, funky changes in harmonic structure at the onset of overload, etc.

Running the subwoofer(s) about 5-10 dB below the max limits tends to work pretty **** well in my experience. Understressed subs always sound clean/uncompressed/linear under actual use. 

These output tests are just a relative tool for sizing the subwoofer for a given application. If subwoofer A maxes out 13 dB higher than subwoofer B at most frequencies, you can bet subwoofer A will be more suitable for larger rooms at higher playback volumes. 

Beyond that, not a huge amount can be subjectively inferred from the results unless the tests were also conducted at lower drive levels which might reveal an inherent defect/flaw in the subwoofer which is present at all playback levels.


----------



## Ilkka

I heard that some people over at the other forum can not understand why the HSU VTF-3 MK3 performed better at 20 Hz without than with the 'turbo'. There also seems to be some uncertainly about the actual tuning frequencies. Well since I have the sub and the turbo here, I measured them.

Without the turbo (both ports open) tuning frequency is around 22.6 Hz, not 25 Hz.










With the turbo (both ports open) tuning frequency is around 17.2 Hz, not 18 Hz.










When looking at these numbers, it should be pretty easy to understand why the non-turbo version performs better all the way down to ~20 Hz. Naturally below 20 Hz the turbo version has more output, as it should have.

Below ~18-20 Hz the turbo version has ~12 dB more clean output. That's even more than HSU claims.


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## Manic Miner

Thanks for the clarification Illka, do you still have the PB12-NSD and the possibility to measure its tuning frequency as well?


----------



## Ilkka

Manic Miner said:


> Thanks for the clarification Illka, do you still have the PB12-NSD and the possibility to measure its tuning frequency as well?


No, but I think Ed can tell it? I think it's around 18 Hz.


----------



## Ed Mullen

Ilkka said:


> No, but I think Ed can tell it? I think it's around 18 Hz.



Yes, it's around 18 Hz - I can measure it later but that's pretty close. 

Picking up the conversation at AVS re: the VTF-3MK3, since the native tune is closer to 20 Hz than the lowered tune, it doesn't surprise me HF was able to push the lower tune louder than the native tune before encountering audible artifacts, despite the fact that the native tune has superior distortion-limited output at 20 Hz.


----------



## Guest

Mark Seaton said:


> Parallel to Ilkka's response above, I'd caution against going on a witch hunt for higher order harmonics.  Basically what you will see is the character/spectral change as the subs are notably overdriven at various frequencies. The ones with predominantly lower order harmonics will probably work a little better when budget and/or space dictate that they will be used in insufficient quantity to meet the listening levels of the user. The subs that eventually exhibit higher order distortion will more clearly "let you know" when you've pushed them too far. Arguements could be made for both cases. The first example above leaves the listener blissfully ignorant of the limiting other than the bass will no longer get louder and it will compress. Blissful ignorance still leaves the listener in bliss, and I think the behavior can definitely be preferred over other overload conditions, especially in more budget concious offerings.
> 
> The important thing to realize is that some frequency overloading with higher order harmonics doesn't mean it can't be very well behaved at levels below that threshold.


I appreciate the jist of your excellent comment and agree bad behaviour near the threshold doesn't mean you can't have good results at lower levels. On the other hand with hot soundtracks all subs are pushed to very high SPLs, especially if one enjoys reference levels. Low order or even order harmonics are hard to discern and can even add to a pleasing sonic experience. At high SPL below the limits subs with higher order distortion don't need to be overdriven to be audibly unpleasant. Rather than add more subs or lower volumes, it would be good to know in advance which subs exhibit more annoying higher order distortion when pushed hard. Like output data, this information would be useful when comparing subs. The old way of looking comparing THD lumped all benign and annoying harmonics together when perhaps a more revealing look would be to focus on the offensive higher/odd orders. Not all distortion is created or sounds the same. CEA-2010 testing provides this additional information which is just as revealing as the weighted average output numbers IMO. Its not so much a witchhut as looking at sub measurments in a way which more clearly distinguishes performance in room.


----------



## craigsub

Ilkka ... GREAT stuff. Yes, people will get wound up over a dB or 2 one way or another. The question in the other forum was trying to draw a correlation in measured distortions to an abritary percentage vs. listening for any noise: distortion, port noise ... etc ... Which is impossible to do.

In regards to the Hsu with and without Turbo ... trying to find the exact right place to measure is not an easy task - but at the MOST, there will be about a 2 dB difference in output measured, depending on the microphone placement, certainly not enough to warrant a lot of upset.

Love your sonotube ESB ... The striping effect gives it a domestic touch. I showed my wife, and she still said over her dead body, but I thought it looked pretty cool. 

Are we going to see some of the Mark Seaton creations in your September shootout ?


----------



## Ilkka

craigsub said:


> Ilkka ... GREAT stuff. Yes, people will get wound up over a dB or 2 one way or another. The question in the other forum was trying to draw a correlation in measured distortions to an abritary percentage vs. listening for any noise: distortion, port noise ... etc ... Which is impossible to do.
> 
> In regards to the Hsu with and without Turbo ... trying to find the exact right place to measure is not an easy task - but at the MOST, there will be about a 2 dB difference in output measured, depending on the microphone placement, certainly not enough to warrant a lot of upset.


Hi Craig, and welcome to the HT Shack.

It's impossible to keep the exact 2m distance to all the radiating elements unless they are on the same baffle. If they aren't, I try to measure the distance from the element that produces MOST of the sound. In a vented enclosure the driver still produces around 90% of the output while the port only contributes around the tuning frequency. IMO it's more important that the driver is as close to 2m distance as possible. 0.1 m or 0.2 m added distance to other elements (like in the case with side ported HSU) doesn't make a huge error, below 1 dB actually.

In any case, I was pleasantly surprised how well the VTF-3 MK3 performed. Currently it's playing in my living room right next to an SVS PB12-Plus/2. Subjectively it sounds really good too. I will take some movie play back max SPL readings tonight.

I will also compare it to the Rythmik Audio's Servo 12" kit and to my own DIY sub. 


> Love your sonotube ESB ... The striping effect gives it a domestic touch. I showed my wife, and she still said over her dead body, but I thought it looked pretty cool.


Actually that's not my sonosub, I have only designed it. It belongs to a friend of mine.

My own DIY subwoofer is the sealed dual TC-2000 15".












> Are we going to see some of the Mark Seaton creations in your September shootout ?


Mark's sub was already invited this time, but I'll let Mark to post the rest.

I'm hoping that AV123's MFW-15 and BMF-1 could also join.  I know that the new SVS Ultra will be there so it would make a very interesting measuring session.


----------



## Manic Miner

I popped by the finnish subwoofer forum the other day, and even though I don't understand more than a couple of words in finnish I got a good laugh from a post with picture comparision












:neener: :jump:


----------



## Ilkka

Manic Miner said:


> I popped by the finnish subwoofer forum the other day, and even though I don't understand more than a couple of words in finnish I got a good laugh from a post with picture comparision
> 
> :neener: :jump:


Yeah, one guy though there's a some sort of resemblance. I don't know what he is talking about...? :coocoo: addle:


----------



## craigsub

Ilkka - I thought they were both yours. My bad. :duh: The dual sealed is gorgeous, and is also a clever design. I think I "have it" as to how you placed the microphone in reference to the driver (You placed it 2 meters from the side of the 3.3, and not the front, right?) ... so yes, there will be less than a 1 dB variance between the subs. 

I will be grabbing an Ultra as soon as they come out - and I think the MFW-15 will be ready for your Fall shootout, we will have one here ... The BMF seems to be taking some time to get worked into something readily manufactured. 

Glad to read that you are going to follow up with some in room movie measurements, too. 

Great smilies in the Shack. I think this guy is a relative of mine ... :jump:


----------



## craigsub

Manic Miner said:


> I popped by the finnish subwoofer forum the other day, and even though I don't understand more than a couple of words in finnish I got a good laugh from a post with picture comparision
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> :neener: :jump:


Does this mean Ilkka built one of those Brown Note subs ?


----------



## Manic Miner

Hihihi, talking about Mythbusters. In a recent episode there was a guy named Illka that even looked a bit like Mr Rissanen, and he did talk geek so for a moment I thought that I knew someone that was on TV

And yes, the smilies are incredible, I almost feel like using them all at once:1eye:


----------



## Ilkka

craigsub said:


> I think I "have it" as to how you placed the microphone in reference to the driver (You placed it 2 meters from the side of the 3.3, and not the front, right?) ... so yes, there will be less than a 1 dB variance between the subs.


Correct.


----------



## Ilkka

Manic Miner said:


> Hihihi, talking about Mythbusters. In a recent episode there was a guy named Illka that even looked a bit like Mr Rissanen, and he did talk geek so for a moment I thought that I knew someone that was on TV
> 
> And yes, the smilies are incredible, I almost feel like using them all at once:1eye:


I haven't seen that on. Which episode was it?


----------



## Manic Miner

It's episode 508, his name is Ilkka Koskelo


----------



## Ilkka

Just a "funny" fact. Want to guess how much raw data was gathered during the weekend?

Answer: 1.15 GB, yes that's gigabytes. :raped:


----------



## Ilkka

I am going to tease you a bit. :R 

When talking about good extension, the Rythmik Audio Servo 12" kit comes to mind. -6 dB point of ~12.5 Hz when crossover set to max (160 Hz) and around 10 Hz when set to min (40 Hz). :hail:


----------



## jmcomp124

Ilkka,
Have you talked to TC sounds about your issue?
Can you share with us now?
You have us waiting .
-Jai


----------



## bossobass

Exocer said:


> Wow, that sealed Tumult did incredibly well (so far) beating out the ported HSU accross the board...


Just add 18dB or so to those numbers as well as many combinations of preset Q and F3 and, voila. It's my system. Not bad in a pinch.

Ilkka...you only measured the sealed subs to 12.5Hz?

Nice thread.

Nice to hear from you, Sir Edward.

Craig, Peter, Seaton and the whole gang. Looking forward to details.

Thanks, Ilk

Bosso


----------



## Ilkka

jmcomp124 said:


> Ilkka,
> Have you talked to TC sounds about your issue?
> Can you share with us now?
> You have us waiting .
> -Jai


I've tried to reach Kyle through their forum and e-mail with no success.


----------



## Ilkka

bossobass said:


> Ilkka...you only measured the sealed subs to 12.5Hz?


No.  I also have 10 Hz numbers. Though I don't think it's worth posting them since even the best one had only ~88 dB (peak) output there.


----------



## jmcomp124

Ilkka said:


> I've tried to reach Kyle through their forum and e-mail with no success.


It takes a very long time to get answers from their forum. You may want to give Heather a call and ask for Kyle's cell #. That is the quickest way of reaching him.


----------



## Kevin_Wadsworth

bossobass said:


> Just add 18dB or so to those numbers as well as many combinations of preset Q and F3 and, voila. It's my system. Not bad in a pinch.


So, when is your system going on sale, Bosso? :newspaper:


----------



## steve nn

Dang! Something is definitely off there Ilkka. You didn't happen to use one of your amps for the Tum reading did you? Can you answer if it was Ok at higher FR? I cant imagine you having the dips misconfigured.


----------



## mazersteven

Hello Everyone,

What is happening in here? :joke:


----------



## bossobass

Ilkka said:


> No.  I also have 10 Hz numbers. Though I don't think it's worth posting them since even the best one had only ~88 dB (peak) output there.


But if you add 6dB, 8dB, 10dB, 12dB with the L/T...

Will you get a chance to measure your sub with a 1 octave boost as you said earlier you might do?

It will probably max out at the same level, but the THD, roll off and response would be cool to compare.

Bosso


----------



## WillyD

jmcomp124 said:


> It takes a very long time to get answers from their forum. You may want to give Heather a call and ask for Kyle's cell #. That is the quickest way of reaching him.


He is probably hesitant to give them a call due to the $$$, but I was gonna suggest trying to contact Heather as well (email/pm). I hope this situation is taken care of. :mooooh:


----------



## jmcomp124

WillyD said:


> He is probably hesitant to give them a call due to the $$$, but I was gonna suggest trying to contact Heather as well (email/pm). I hope this situation is taken care of. :mooooh:


He can use Skype VOIP whatever and they are not that expensive at all considering what he has invested in these woofers. TC needs to address Ilkkas issues quickly.


----------



## WillyD

jmcomp124 said:


> He can use Skype VOIP whatever and they are not that expensive at all considering what he has invested in these woofers. TC needs to address Ilkkas issues quickly.


Very good point, and I agree entirely. I really hope TC attends to him asap.


----------



## RuneW

jmcomp124 said:


> He can use Skype VOIP whatever and they are not that expensive at all considering what he has invested in these woofers. TC needs to address Ilkkas issues quickly.


My experience is that their drivers are better than their communication skills...:waiting:

Let's hope that they realize that quite a few potential customers are following this thread!


----------



## Ilkka

steve nn said:


> Dang! Something is definitely off there Ilkka. You didn't happen to use one of your amps for the Tum reading did you? Can you answer if it was Ok at higher FR? I cant imagine you having the dips misconfigured.


Sorry Steve but now you lost me. What do you mean?

What is off?


----------



## Ilkka

bossobass said:


> But if you add 6dB, 8dB, 10dB, 12dB with the L/T...
> 
> Will you get a chance to measure your sub with a 1 octave boost as you said earlier you might do?
> 
> It will probably max out at the same level, but the THD, roll off and response would be cool to compare.
> 
> Bosso


The L/T only changes the frequency response, it doesn't change the max output at any frequency.

I might measure the L/T'ed version next weekend.


----------



## Ilkka

jmcomp124 said:


> It takes a very long time to get answers from their forum. You may want to give Heather a call and ask for Kyle's cell #. That is the quickest way of reaching him.


I have reached Kyle. Now we just have to find out what the he** is going on with those TC-2000's...

All of them are okay, so this isn't a failure issue. It's just that some of them measured as the model suggest, but some didn't (both sealed). Also the single driver TC-2000 performed somewhat better at some frequencies (especially low) than the dual driver sub. Also the frequency responses are very different (which no model suggests). I'm suspecting one or more of the drivers isn't up to its specs. Probably much higher Qts than announced. He (my friend who's sub that is) already had one bad motor (demagnetized magnets) but that was swapped. Maybe this new motor isn't still good.


----------



## Manic Miner

For those who have not noticed, avtalk have published the results from their latest test

http://www.avtalk.co.uk/forum/index.php?t=thread&frm_id=50&rid=0&SQ=0

Finally we have some numbers on a Sunfire sub


----------



## Ilkka

Manic Miner said:


> For those who have not noticed, avtalk have published the results from their latest test
> 
> http://www.avtalk.co.uk/forum/index.php?t=thread&frm_id=50&rid=0&SQ=0
> 
> Finally we have some numbers on a Sunfire sub


Than you for advertising their tests in my subwoofer tests thread. addle: :sarcastic:


----------



## Manic Miner

I you want me to, I'll remove the post, but then again, you're a moderator so I guess you could do it yourself if you felt like it. Now all I need to deicide as what emoticon expresses my feelings.......think I'll go with this one :innocent: 

What I was hoping for were some comments on the Sunfires performance, or should I say lack of performance :devil: All those watts, 2.35" of stroke, and a PR, and the measured result is hardly any better than that of the SPL1000-R?


----------



## Ilkka

Here is some more info about the TC-2000 situation.

The single driver sub has the DVC 15" version of the TC-2000 in a 90L (net) enclosure (front firing). A single ~1800W amp was used to power it (8 ohms bridged).

The dual driver sub has two SVC 15" versions of the TC-2000 in a 140L (net) enclosure (opposed firing). Two ~2200W amps were used to power it (both 4 ohms bridged).

Both WinISD and Unibox suggest that the DVC version needs a little bit more volume for the same Qtc (around 90L vs. 70L for 0.7Q single driver). That means that both subs should have pretty much identical frequency responses.

Below are the frequency responses I measured last weekend.










As you can see, the single driver sub has much flatter response and the inductance peak is around 10 Hz lower. No model suggest that large difference between them. And actually the dual driver sub measures really close to the Unibox model. It's the single driver sub that's way off.

When we look at the distortion limited output numbers, the single driver subs kills the dual sub below 40 Hz, as the frequency response indicates.

Below is the updated spreadsheet.










At 40 Hz above the dual driver sub is strong but drops below the single driver sub and the Tumult at lower frequencies. Also the single TC-2000 is weaker than the Tumult at every frequency except 12.5 Hz.

What also baffles me is that the single driver sealed TC-2000 is 2-3 dB behind the single driver LLT at 40 Hz and above. 4 ohm vs. 8 ohm shouldn't make that large difference when I know that the amp we used can not output 2x power into 4 ohms, not even close.

If we compare the CEA spectras at 20 Hz, we can see that the dual driver sub is actually a lot cleaner than the single driver sub, but it has more 2nd order distortion. Actually that is the case at every frequency below 40 Hz.

CEA spectra for the single driver TC-2000. Output capped by the 9th and 10th harmonic.










CEA spectra for the dual driver TC-2000. Output capped by the 2nd harmonic.


----------



## Ilkka

Here's the frequency response for the third TC-2000, the 'LLT'.


----------



## bobgpsr

Ilkka said:


> Here's the frequency response for the third TC-2000, the 'LLT'.


Very nice. To me it looks like it meets the Steve Callas criteria. Way to go DIY'er. :clap:


----------



## Ilkka

bobgpsr said:


> Very nice. To me it looks like it meets the Steve Callas criteria. Way to go DIY'er. :clap:


Speaking of the :devil:, where is Steve?


----------



## Blaser

> Both WinISD and Unibox suggest that the DVC version needs a little bit more volume for the same Qtc (around 90L vs. 70L for 0.7Q single driver). That means that both subs should have pretty much identical frequency responses.


The difference in volume is pretty small:dunno: and without a software, I would think this is probably the problem in fact:scratch: 

Blaser


----------



## jmcomp124

Ilkka said:


> Here is some more info about the TC-2000 situation.
> 
> The single driver sub has the DVC 15" version of the TC-2000 in a 90L (net) enclosure (front firing). A single ~1800W amp was used to power it (8 ohms bridged).
> 
> The dual driver sub has two SVC 15" versions of the TC-2000 in a 140L (net) enclosure (opposing firing). Two ~2200W amps were used to power it (both 4 ohms bridged).
> 
> Both WinISD and Unibox suggest that the DVC version needs a little bit more volume for the same Qtc (around 90L vs. 70L for 0.7Q single driver). That means that both subs should have pretty much identical frequency responses.
> 
> Below are the frequency responses I measured last weekend.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> As you can see, the single driver sub has much flatter response and the inductance peak is around 10 Hz lower. No model suggest that large difference between them. And actually the dual driver sub measures really close to the Unibox model. It's the single driver sub that's way off.


Puzzling indeed. "Just to make sure", in case they are operating out of phase due to some miswiring inside the driver, can you switch the polarity at one of the driver terminals and see what happens?

Using WinISD, Qms (calculated based on Qts and and Qes) is a negative value of -4.284.
Is this valid? 
It does make me wonder if the Qts and Qes values are right.
Thanks,
-Jai


----------



## Ilkka

jmcomp124 said:


> Puzzling indeed. "Just to make sure", in case they are operating out of phase due to some miswiring inside the driver, can you switch the polarity at one of the driver terminals and see what happens?


I'm 100% sure they weren't operating out of phase.



> Using WinISD, Qms (calculated based on Qts and and Qes) is a negative value of -4.284.
> Is this valid?
> It does make me wonder if the Qts and Qes values are right.
> Thanks,
> -Jai


I get +4.284?


----------



## Ilkka

Here's the Unibox simulation for the dual driver sub. Looks pretty similar.


----------



## jmcomp124

Ilkka said:


> Here is some more info about the TC-2000 situation.
> 
> The single driver sub has the DVC 15" version of the TC-2000 in a 90L (net) enclosure (front firing). A single ~1800W amp was used to power it (8 ohms bridged).
> 
> The dual driver sub has two SVC 15" versions of the TC-2000 in a 140L (net) enclosure (opposing firing). Two ~2200W amps were used to power it (both 4 ohms bridged).


For an "apple" to "more apples" comparison, it should have been

The single driver sub has the SVC 15" version of the TC-2000 in a 90L (net) enclosure (front firing). A single ~2200W amp was used to power it (4 ohms bridged).

The dual driver sub has two SVC 15" versions of the TC-2000 in a 140L (net) enclosure (opposing firing). Two ~2200W amps were used to power it (both 4 ohms bridged).

I don't know how much of a difference it would make, but if you can use one of the SVC drivers in the single driver sub and the 2200W amplifier, that may have some answers.
Just a thought.


----------



## Ilkka

jmcomp124 said:


> For an "apple" to "more apples" comparison, it should have been
> 
> The single driver sub has the SVC 15" version of the TC-2000 in a 90L (net) enclosure (front firing). A single ~2200W amp was used to power it (4 ohms bridged).
> 
> The dual driver sub has two SVC 15" versions of the TC-2000 in a 140L (net) enclosure (opposing firing). Two ~2200W amps were used to power it (both 4 ohms bridged).
> 
> I don't know how much of a difference it would make, but if you can use one of the SVC drivers in the single driver sub and the 2200W amplifier, that may have some answers.
> Just a thought.


That is the same amp, 1800W vs. 2200W difference comes from the 4ohm/8ohm load. And maximum power doesn't affect the frequency response.

We will try my SVC driver in my friend's 90L cabinet. But I'm pretty sure 20L difference doesn't do much.


----------



## jmcomp124

Ilkka said:


> That is the same amp, 1800W vs. 2200W difference comes from the 4ohm/8ohm load. And maximum power doesn't affect the frequency response.
> 
> We will try my SVC driver in my friend's 90L cabinet. But I'm pretty sure 20L difference doesn't do much.


I agree, but this would be worth a try.


----------



## Mark Seaton

Ilkka said:


> Here is some more info about the TC-2000 situation.
> 
> The single driver sub has the DVC 15" version of the TC-2000 in a 90L (net) enclosure (front firing). A single ~1800W amp was used to power it (8 ohms bridged).
> 
> The dual driver sub has two SVC 15" versions of the TC-2000 in a 140L (net) enclosure (opposing firing). Two ~2200W amps were used to power it (both 4 ohms bridged).
> 
> Both WinISD and Unibox suggest that the DVC version needs a little bit more volume for the same Qtc (around 90L vs. 70L for 0.7Q single driver). That means that both subs should have pretty much identical frequency responses.
> 
> Below are the frequency responses I measured last weekend.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> As you can see, the single driver sub has much flatter response and the inductance peak is around 10 Hz lower. No model suggest that large difference between them. And actually the dual driver sub measures really close to the Unibox model. It's the single driver sub that's way off.


Hi Ilkka,

That single driver certainly isn't an on-spec TC-2000. A quick model suggests that the driver is most certainly much heavier, probably by ~100g, and likely has a much softer suspension. Who knows, maybe it's a 3000 coil on a 2000 frame. :scratchhead: 

The smaller volume per driver would show some increase in distortion, but that seems higher than it should be, especially in relation to the other alledgedly similar driver. The numbers from the big vented TC-2k suggest a useful peak excursion around 28-30mm, where the lower frequency, dual driver limit is probably less than 1/2 that. How did the dual driver sub fair vs. the single in the sweeps at increasing output?

While I wouldn't expect it to make a big difference, did you happen to try driving both drivers from a single amp (maybe wired in series) to insure the drive from the amp wasn't contributing to the results? I somewhat doubt it as the output up high would likely have been affected.

The simple conclusion is that something is certainly off spec on the single driver sub (in a good way in this case) and something could also be off with your pair of drivers. If possible, the next thing to do is to take some in-box and free air impedance measurements of the drivers to see the differences. I do think it's imporant for readers to remember that exceedingly few DIYers do any in-depth confirmation of the system's performance, so most would never identify these issues.


----------



## jmcomp124

Mark Seaton said:


> Hi Ilkka,
> ......The simple conclusion is that something is certainly off spec on the single driver sub (in a good way in this case) and something could also be off with your pair of drivers. If possible, the next thing to do is to take some in-box and free air impedance measurements of the drivers to see the differences. I do think it's imporant for readers to remember that exceedingly few DIYers do any in-depth confirmation of the system's performance, so most would never identify these issues.


This is exactly the reason why I want to learn how Ilkka does these measurements. Maybe sometimes ignorance is bliss, but unless you measure, how would you know.


----------



## Ilkka

Mark Seaton said:


> Hi Ilkka,
> 
> That single driver certainly isn't an on-spec TC-2000. A quick model suggests that the driver is most certainly much heavier, probably by ~100g, and likely has a much softer suspension. Who knows, maybe it's a 3000 coil on a 2000 frame. :scratchhead:


Thanks Mark. Could it also be less flow in the gap? That would cause higher Qts which would make the frequency response extend lower.

The motor that came with the driver was demagnetized (or never was magnetized). TC swapped it so I know the coil isn't at least a 3000 coil. Here's a picture of it.












> The smaller volume per driver would show some increase in distortion, but that seems higher than it should be, especially in relation to the other alledgedly similar driver.


At the same output level the dual driver sub should still be ahead in distortion limited output even with slightly less volume per driver. 



> The numbers from the big vented TC-2k suggest a useful peak excursion around 28-30mm, where the lower frequency, dual driver limit is probably less than 1/2 that. How did the dual driver sub fair vs. the single in the sweeps at increasing output?


I wasn't able to push them into full compression at low frequencies since I wasn't using any EQ. Amps clipped already up higher. The maximum level that I recorded at 20 Hz was 102 dB for the single driver subs and 106 dB for the dual driver sub. AA Tumult did 101 dB.



> While I wouldn't expect it to make a big difference, did you happen to try driving both drivers from a single amp (maybe wired in series) to insure the drive from the amp wasn't contributing to the results? I somewhat doubt it as the output up high would likely have been affected.


I checked that (with a DMM) both amps did output the same voltage, but that's all. At home I've been using a single amp (both in series and parallel). I doubt that was the problem. 



> The simple conclusion is that something is certainly off spec on the single driver sub (in a good way in this case) and something could also be off with your pair of drivers. If possible, the next thing to do is to take some in-box and free air impedance measurements of the drivers to see the differences. I do think it's imporant for readers to remember that exceedingly few DIYers do any in-depth confirmation of the system's performance, so most would never identify these issues.


I have already taken an in-box impedance measurement for my dual driver sub. I will take the rest when I visit my friend.


----------



## jmcomp124

If this type of testing (which we all know is very rare to find) reveals a difference between the SVC and DVC drivers (if there is indeed one) and we may end up learning that there is a difference between the two. At least as of now that's what the data appears to allude. 

This begs the question, how much difference is there indeed between a TC2K, a TC3K and an LMS 5400 in real life. Models use parameters and one issue is that the parameters maybe off and a model is no substitute to real world measurements. All that we can do is hope that the parameters are right and that the model is as close to real world. 

Ilkka, is there a possibility of you measuring an LMS 5400 anytime soon?
Being their flagship product, this would be something very useful to me and a lot of other folks reading this. According to my knowledge and based on inputs, there is no other driver in the USA that is available to DIYers, that matches or beats the LMS 5400 in that price range.

But this driver has not seen a ruler like yours. So it still remains just a claim only backed up by specs and a few DIYers who have tried it and are happy but have not done extensive measurements like yours. :waiting:


----------



## Ilkka

jmcomp124 said:


> Ilkka, is there a possibility of you measuring an LMS 5400 anytime soon?
> Being their flagship product, this would be something very useful to me and a lot of other folks reading this. According to my knowledge and based on inputs, there is no other driver in the USA that is available to DIYers, that matches or beats the LMS 5400 in that price range.


I originally wanted to use the LMS-4100 NEO drivers in my dual driver sub, but since they were delayed so many times, I decided to try the TC-2000's first.

The LMS-5400 is a little bit too expensive for me to buy just for a test. If TC-Sounds wants to send me one, I'd be happy test it.


----------



## Mark Seaton

Ilkka said:


> Thanks Mark. Could it also be less flow in the gap? That would cause higher Qts which would make the frequency response extend lower.
> 
> The motor that came with the driver was demagnetized (or never was magnetized). TC swapped it so I know the coil isn't at least a 3000 coil. Here's a picture of it.


If the motor never made it to the magnetizer, who knows what else was wrong. It's somewhat possible that low BL, combined with a much softer suspension could give the response you measured, but tough to say without seeing a comparison of the impedance curves. Which of the drivers you and your friend have had to have the motor replaced? Just his in the 90L box?



> I wasn't able to push them into full compression at low frequencies since I wasn't using any EQ. Amps clipped already up higher. The maximum level that I recorded at 20 Hz was 102 dB for the single driver subs and 106 dB for the dual driver sub. AA Tumult did 101 dB.


Maximum output from a swept sine seems reasonable given the available power, response curves, and assuming some compression at those levels. BTW, was the Tumult driven with the same amp as the TC-2000 subs? There are a few reasons for excessive 2nd order distortion, and testing one or both of your drivers in the 90L box would give a more direct indication.


----------



## Ilkka

Mark Seaton said:


> If the motor never made it to the magnetizer, who knows what else was wrong. It's somewhat possible that low BL, combined with a much softer suspension could give the response you measured, but tough to say without seeing a comparison of the impedance curves. Which of the drivers you and your friend have had to have the motor replaced? Just his in the 90L box?


Yes, just his. I have measured that my drivers are pretty much identical compared to each other.



> Maximum output from a swept sine seems reasonable given the available power, response curves, and assuming some compression at those levels. BTW, was the Tumult driven with the same amp as the TC-2000 subs? There are a few reasons for excessive 2nd order distortion, and testing one or both of your drivers in the 90L box would give a more direct indication.


The Tumult was driven with a Yamaha M-85 stereo amplifier. It's very old but pretty powerful amp. The Tumult has 2x2 ohm coils, so I'm guessing around 2x600W RMS.


----------



## steve nn

> Sorry Steve but now you lost me. What do you mean?
> 
> What is off?


Sorry Ilk, I was referring to max SPL that you brought up earlier. It seems to be the jest of the conversation.....


----------



## Ilkka

steve nn said:


> Sorry Ilk, I was referring to max SPL that you brought up earlier. It seems to be the jest of the conversation.....


So why you are thinking that max SPL was off? Is it too high or low? :scratchhead:


----------



## SteveCallas

I'll come out of hiding for a few random comments.

When posted, this latest round of testing will only serve to yet again confirm why Ilkka is the absolute best resource we subwoofer enthusiasts have. He contributes significantly more to this area of interest than anyone, bar none. It's not just these subwoofer shootouts either, when a topic of debate comes up, like electronics rolloff, DRC, dissimilar results from two other parties, or group delay in port use, he's kind enough to take some measurements to prove things one way or the other. And many times he does it while taking grief from some of the jokers that like to frequent some of the other forums as well. So to start, big thumbs up to Ilkka :T 

Next, reading through this thread, the XYZ company trying to boast about high frequency output from their product is kind of funny, as the DIY subs show that a legitimate subwoofer can best that product and stay pretty linear into the teens as well, thus making it seem rather useless. But I don't want to get sidetracked so soon, I'm only just starting :R 

Though not much data has been posted yet, I can't imagine the LLT performing poorly, it will probably do very well....likely the best single driver sub and best performer per dollar tested by a wide margin. That said, the design isn't exactly optimized for the driver in my opinion. Had a larger enclosure with a lower tune been used, I believe the results would be even more impressive in terms of low end output and the onset of port compression. An ideal LLT would be able to effectively use a large enough port to all but eliminate compression, but that's a little difficult to pull off with the TC2000 and RL-p15. No big deal though. 

It will be interesting to see if my stance on amp limiting LLTs wasn't really even necessary, perhaps even detrimental to max performance. It would be a simple fix for owners in terms of bridging an amp or buying a second, but this is the topic I am probably looking forward to most.

Distortion limited output of sealed 15" drivers with low end boosting will be very informative me thinks :devil: 

I also believe this round of testing will go to show that simulations are more accurate than some like to give them credit for. Based on the direct comparison of a sealed TC 2000 and a LLT version, extrapolations in other circumstances will gain a lot more legitimacy.

As for the comments on the LMS 18" being the best driver out there, I'd put the XXX 18" with xbl^2 and 54mm xmax above it.

I'd have to think this type of testing with some quality diy subs won't exactly make some companies very happy :bigsmile: You'll always have a group who isn't interested in building anything, but more and more people have been making the switch to diy, and I'd have to think this would push over another nice big chunk who were sitting on the edge. 

Anyway, thanks again for all the work Ilkka, can't wait to see the full spectrum of data.


----------



## shr-t

Manic Miner said:


> I popped by the finnish subwoofer forum the other day, and even though I don't understand more than a couple of words in finnish I got a good laugh from a post with picture comparision
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> :neener: :jump:


I was the one to make up that pic of the "twins" :R :rofl2: Just couldn't help noticing the resemblence. But those endcaps are actually pretty ingenious, I'm a bit tired of vertical, all-black sonos..

Hope you get the driver issue sorted out, sounds like something is off with the single driver, which actually seems positive in this case, if one looks at the FR graph. Mark has made some good guessed about what could be wrong, I second those.


Too many smilies here at HTS to choose from :coocoo:


----------



## SteveCallas

If the end user will be using EQ to flatten in room response of a sealed sub, the differences in the natural FR of the TC 2000 driver won't really matter too much, as output at a given frequency will still be based on excursion. The distortion differences should be negligible at best. With distortion being a good indicator of excursion in a sealed sub, we can extrapolate all we need to make comparisons - hopefully Ilkka will post all the data and not wait on a resolution from TC Sounds (cough..hint, wink).


----------



## steve nn

> So why you are thinking that max SPL was off? Is it too high or low?


No I haven't been following close enough as the conversation transpires. You summed things up in this post and what is contained beyond.



> As you can see, the single driver sub has much flatter response and the inductance peak is around 10 Hz lower. No model suggest that large difference between them. And actually the dual driver sub measures really close to the Unibox model. It's the single driver sub that's way off.
> 
> When we look at the distortion limited output numbers, the single driver subs kills the dual sub below 40 Hz, as the frequency response indicates.
> 
> Below is the updated spreadsheet.





> I'd have to think this type of testing with some quality diy subs won't exactly make some companies very happy You'll always have a group who isn't interested in building anything, but more and more people have been making the switch to diy, and I'd have to think this would push over another nice big chunk who were sitting on the edge.


Hey Steve is that you? Well please! dont you forget how easily the LLT bottoms:whistling: Good to see ya Steve.


----------



## SteveCallas

steve nn said:


> Hey Steve is that you? Well please! dont you forget how easily the LLT bottoms Good to see ya Steve.


Oh yeah, almost forgot a couple more random thoughts. Without trying to stir the pot too much, seeing as the TC 2000 and RL-p15 are VERY similar drivers, this testing should reveal a half hearted attempt at diy to be what most of us knew it was going to be.

Also, the exact design of this LLT being tested is what your old buddy Steve nn almost made available to US customers for $1000 shipped to your door as a very sexy black on black sonosub. Things unfortunately didn't work out, but when you look at what commercial manufacturers are offering for $1000 (including shipping), and then see what this thing can do, Steve would have been a very popular guy me thinks :yes:

Good to see you too!


----------



## Ilkka

SteveCallas said:


> The distortion differences should be negligible at best. With distortion being a good indicator of excursion in a sealed sub, we can extrapolate all we need to make comparisons - hopefully Ilkka will post all the data and not wait on a resolution from TC Sounds (cough..hint, wink).


I just plotted some distortion sweeps. Some really interesting info there... :nerd:


----------



## Ilkka

steve nn said:


> Well please! dont you forget how easily the LLT bottoms:whistling: Good to see ya Steve.


Well actually we did bottom out the LLT while taking the compression sweeps... That happened around 30 Hz and 113 dB level (RMS).

edit: Further research showed that it didn't bottom. It was the amp that clipped.


----------



## steve nn

> Well actually we did bottom out the LLT while taking the compression sweeps... That happened around 30 Hz and 113 dB level (RMS).


Yeah but if memory serves me correct, you had a couple K?? of juice flowing didn't you?


----------



## SteveCallas

Interesting - I seem to recall telling that certain someone that the bottoming they were experiencing was coming from above tuning, not below. The way they wired the driver and the amount of power they supplied it would cause it to bottom above tuning when playing the same WotW scene over and over and increasing the volume.


----------



## Ilkka

steve nn said:


> Yeah but if memory serves me correct, you had a couple K?? of juice flowing didn't you?


Yes, a ~2000W amp was used. Don't know the real input power at that point though.


----------



## steve nn

> One interesting note. The large TC-2000 15" based sonosub was clipping its ~2000W amp at 40 Hz and above.


I would hope it would bottom, but I'd say it held in there pretty good considering.onder:

EDIT> I see we posted at the same time Ilkka


----------



## Mark Seaton

SteveCallas said:


> If the end user will be using EQ to flatten in room response of a sealed sub, the differences in the natural FR of the TC 2000 driver won't really matter too much, as output at a given frequency will still be based on excursion. The distortion differences should be negligible at best. With distortion being a good indicator of excursion in a sealed sub, we can extrapolate all we need to make comparisons - hopefully Ilkka will post all the data and not wait on a resolution from TC Sounds (cough..hint, wink).


Steve,

If we consider the possible causes of the measured differences, it should be very clear that these are different drivers, and I wouldn't expect them to have similar distortion characters at all. The high second order distortion of Ilkka's woofers could also indicate a few other things that will only be clear if one of the drivers are dropped in the 90L enclosure for direct comparison.

While the RL-p15 and TC-2000 bear a family resemblance, they have different coil overhangs, entirely different suspensions and basket, and I can't seem to find any note on SS's page if the RL-p15 is a 2" or 3" VC? Modeling them shows notable differences in response, and I would expect the TC-2000 to have better behavior near and past its linear limits. I'm sure Ilkka's testing will confirm that the sonotube design there is quite a performer, but let's not globally attribute the results of one box to be equal to all vaguely similar designs.

Ilkka's results will confirm what should be the first lesson for anyone interested in subwoofer design... One way or another, be it enclosure, amp or driver, size matters.


----------



## jmcomp124

Mark Seaton said:


> Steve,
> 
> If we consider the possible causes of the measured differences, it should be very clear that these are different drivers, and I wouldn't expect them to have similar distortion characters at all. The high second order distortion of Ilkka's woofers could also indicate a few other things that will only be clear if one of the drivers are dropped in the 90L enclosure for direct comparison.
> 
> While the RL-p15 and TC-2000 bear a family resemblance, they have different coil overhangs, entirely different suspensions and basket, and I can't seem to find any note on SS's page if the RL-p15 is a 2" or 3" VC? Modeling them shows notable differences in response, and I would expect the TC-2000 to have better behavior near and past its linear limits. I'm sure Ilkka's testing will confirm that the sonotube design there is quite a performer, but let's not globally attribute the results of one box to be equal to all vaguely similar designs.
> 
> Ilkka's results will confirm what should be the first lesson for anyone interested in subwoofer design... One way or another, be it enclosure, amp or driver, size matters.


Mark,
You are building a PR based design with the BMF and I am investing big time (at least for me) (being a lowly end user) on a PR based design and I have a very interesting question for you. One of the guys who I really admire and appreciate, has the following statement to say

"A resonant structure with no direct control loop to the stimulation signal is by definition a source of distortion. "

Now that statement, directly points out potential flaws with PR designs (and to some degree ported subs too and maybe even horns). This is no ordinary guy and I won't disclose his identity but he is among your ranks when it comes to subwoofers. I would like to know what your thoughts are on that statement.

Now don't dodge around my question, you know me pretty well by now and I ask pointed questions and do expect direct answers that I sometimes don't get from you,,,,,, (specifically with the PR questions I asked you on avs ) just answer with the first thought that comes to your mind. You wil be doing me a favor. I value your opinions Mark, because I consider you one of the masters of bass and I mean it :whew:
There are very few folks like you out there, so I really hope I can capture what is on your mind. Please excuse my "being so direct". It simply means, I attribute a lot of weight to your thoughts and opinions. So please take this as a compliment. 
One of these days, sooner or later Illkka is going to be testing PR based subs (wishful thinking). It only make sense to do so.


----------



## Chrisbee

Mark Seaton said:


> Steve,
> 
> One way or another, be it enclosure, amp or driver, size matters.


Anything above 16 cubic meters, 1000 Watts and 4 x 15" is a pretty good starting point. :devil:


----------



## steve nn

> Also, the exact design of this LLT being tested is what your old buddy Steve nn almost made available to US customers for $1000 shipped to your door as a very sexy black on black sonosub. Things unfortunately didn't work out, but when you look at what commercial manufacturers are offering for $1000 (including shipping), and then see what this thing can do, Steve would have been a very popular guy me thinks :yes:


Thank you for your kind words Steve, I attribute the design to your direct input and most appreciated advice. It was a fun endeavour, but I quickly learned it's much different building a sub for another party rather than myself.. it has a way of taking the fun out of the project, although it's very gratifying to get the end user impressions over other subs they have had or do have. In the end though, family first subs second.. so maybe in a year or so after the kids start moving out and things get squared away with me and the wife.

With the availability of 18" drivers now, it would be much fun to see what a guy could muster up at a little sacrifice to performance, keeping the enclosure at a manageable size.. well from a DIY'ers perspective anyway.


> and I can't seem to find any note on SS's page if the RL-p15 is a 2" or 3" VC?


Hi Mark...it is 3"


> The LMS-5400 is a little bit too expensive for me to buy just for a test. If TC-Sounds wants to send me one, I'd be happy test it.


Now that would be a treat! Maybe we ought to get a group buy going for a single driver and you be the recipient? For $50, it would certainly be worth it to me over here on the West side.. I mean seriously!


----------



## Ilkka

jmcomp124 said:


> One of these days, sooner or later Illkka is going to be testing PR based subs (wishful thinking). It only make sense to do so.


I have already tested a PR based sub. 

http://www.hometheatershack.com/forums/subwoofer-tests/976-diy-chorus-xp3-clone.html

IMO it performed really well. It could have used a little more beefier amp though. That's the reason for high THD values during 105 dB sweep. The shape of the frequency response is really good and it doesn't ring (spectral decay) as much as many traditional ported systems.


----------



## Ilkka

steve nn said:


> Now that would be a treat! Maybe we ought to get a group buy going for a single driver and you be the recipient? For $50, it would certainly be worth it to me over here on the West side.. I mean seriously!


Hmm, that's not a bad idea. :scratchchin: 

I will contact TC-Sounds and see what they think about it. Maybe we can get a discount. raying: 

Which LMS (15"/18") you people would like to see and what kind of enclosure should I build? Traditional ported is pretty much no go with these puppies. Single 18" sealed? Two 15" in the box I already have?


----------



## Ilkka

jmcomp124 said:


> "A resonant structure with no direct control loop to the stimulation signal is by definition a source of distortion. "


I think I know who said that... :bigsmile:

I think you (Jai) will be pleasantly surprised when you see the distortion sweeps I plotted yesterday.


----------



## brucek

> Which LMS (15"/18") you people would like to see and what kind of enclosure should I build? Traditional ported is pretty much no go with these puppies.


Why is that? Are you including LLT in that statement?

brucek


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## Ilkka

brucek said:


> Why is that? Are you including LLT in that statement?
> 
> brucek


Yes, especially LLT.

They don't like large enclosures and that causes problems with ports i.e. you can't fit a large enough port.

LMS-5400 18" could work in 300L ported tuned to 16 Hz, but then you can use only 6" port which is way too small for an 18".

PR or sealed is the only way to go.


----------



## jmcomp124

Ilkka said:


> I think I know who said that... :bigsmile:
> 
> I think you (Jai) will be pleasantly surprised when you see the distortion sweeps I plotted yesterday.


Thanks for the reassurance. I do get cold feet at time with this project I am embarking on PRs .
Will look forward for it.


----------



## brucek

> Yes, especially LLT.


Yeah, OK, I played around with it a bit and I see what you mean. I guess the real crime there is more of lost opportunity than anything else. That driver can take enormous power and if it's fed that full power in the LLT, the velocity goes to the moon, so the extra benefit of the costly driver is lost in having to back off - you may as well get a cheaper one to do the LLT job..... That's my take anyway...

brucek


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## SteveCallas

Yep. My thing with PRs though is that when you really get down to considering them as an option, needing say two high excursion 18" PRs for one high excursion 15" driver and say three or four PRs for an 18" high excursion driver, the cost of the PRs becomes much more than the cost of the driver, sometimes more than the cost of a finished sub altogether. So in the case of something like the TC 2000 LLT, though I do expect to see a fair amount of compression with that 6" diameter port around tuning at extreme levels, I'd rather build two of those than one PR version, as the additional performance is much more than what I'd have recouped from using a PR over a port. With the LMS 5400 18", I'd just go sealed.



Mark said:


> One way or another, be it enclosure, amp or driver, size matters.


Hency the phrase I have been using for subwoofer performance - if you don't have the size, you must compromise.


----------



## WillyD

> Now that would be a treat! Maybe we ought to get a group buy going for a single driver and you be the recipient? For $50, it would certainly be worth it to me over here on the West side.. I mean seriously!


Yes, I'd contribute to that as well. I'd vote for testing it with a simple well built sealed enclosure, because as Ilkka said, it is pretty much impossible to properly port such a driver. 

Of course one could build say, a 225-250 liter PR enclosure and get insane performance, and still have spent less than that RE XXX driver....:coocoo:


----------



## jmcomp124

steve nn said:


> Now that would be a treat! Maybe we ought to get a group buy going for a single driver and you be the recipient? For $50, it would certainly be worth it to me over here on the West side.. I mean seriously!


Count me in. I will be glad to contribute that $50. However, I do have an additional suggestion. I want to see the performance of PRs too. I am leaning towards one LMS 5400 18" with 2 PRs now. The PRs would be side firing. I will have pre-made covers for the PR slots, in case I decide to go sealed down the line. If Illkka can build something like that too, then he can do measurments with PRs and without PRs (sealed). Maybe also do some double blind test on SQ of sealed vs PRs and this woudl sure be a good myth buster backed by solid measurments. 
I will double my contribution to $100 if the PRs are included as I suggested and if this can be done in the next 2 months. 
Please chip in. This would be well worth it.


----------



## Ilkka

I think the easiest solution would be two 15" drivers since I could drop them in the same box I now have the TC-2000's. Then we would also directly see how they compare to TC-2000's.

A single 15" and two 18" PRs could also work, maybe additional to the dual sealed subwoofer? Something around 5 cu ft and 16-17 Hz tuning looks good. I haven't heard from TC-Sounds yet.

Also when the LMS-4100 NEO is done, I will be getting a pair of those.


----------



## steve nn

> Which LMS (15"/18")


Might as well go for broke and do the 18" of course, it's the driver we have all been wondering about? If we could get enough of a donation going, it could save many of us a good chunk of $$!.. that's if we don't like what you come up with. My thinking is your review could also include your own personal opinion regarding SQ along with what you do best. Anyway, I'll plan on opening up a Thread this weekend with your final OK, or thereafter if warranted? 


> Yes, I'd contribute to that as well. I'd vote for testing it with a simple well built sealed enclosure, because as Ilkka said, it is pretty much impossible to properly port such a driver.


Cool!..put King Willy down for $300:bigsmile: We'll be there in no time the way it's going. Yeah that's my thinking also, say maybe a nice heavy-duty sealed enclosure around 8-9 cu ft?


----------



## steve nn

> I think the easiest solution would be two 15" drivers since I could drop them in the same box I now have the TC-2000's.


I hear ya, but there is only a $100 cost difference between a single 15" versus the 18". It would admittedly require more work on your part, but hey a free LMS-5400:daydream:


----------



## WillyD

> put King Willy down for $300


:rofl2:


----------



## Ilkka

steve nn said:


> Might as well go for broke and do the 18" of course, it's the driver we have all been wondering about? If we could get enough of a donation going, it could save many of us a good chunk of $$!.. that's if we don't like what you come up with. My thinking is your review could also include your own personal opinion regarding SQ along with what you do best. Anyway, I'll plan on opening up a Thread this weekend with your final OK, or thereafter if warranted?


Let's wait until I get a reply from TC-Sounds, ok?



> Cool!..put King Willy down for $300:bigsmile: We'll be there in no time the way it's going. Yeah that's my thinking also, say maybe a nice heavy-duty sealed enclosure around 8-9 cu ft?


IMO 8-9 cu ft is too large for the 18". Something like 5 cu ft looks better. Q is already around 0.6.


----------



## SteveCallas

Since we are all voicing opinions, I'd much rather see an RL-p18 tested than a LMS 5400 18. By the time you factor in proper PR'ing for the 5400, you could buy four RL-p18s. Performance would be much, much greater. 

If the fascination with the LMS driver is just seeing how linear it is over the claimed xmax, get the 15" and save some :spend: If it is best performance per dollar (which I've noticed is almost never the case, though it is often claimed to be), the LMS drivers should be easily beaten by other options :dontknow:


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## Ilkka

SteveCallas said:


> Since we are all voicing opinions, I'd much rather see an RL-p18 tested than a LMS 5400 18. By the time you factor in proper PR'ing for the 5400, you could buy four RL-p18s. Performance would be much, much greater.
> 
> If the fascination with the LMS driver is just seeing how linear it is over the claimed xmax, get the 15" and save some :spend: If it is best performance per dollar (which I've noticed is almost never the case, though it is often claimed to be), the LMS drivers should be easily beaten by other options :dontknow:


My friend is already building a LLT using an RL-p18, so we have that one covered.


----------



## WillyD

SteveCallas said:


> If it is best performance per dollar (which I've noticed is almost never the case, though it is often claimed to be), the LMS drivers should be easily beaten by other options :dontknow:


So you have distortion results/tests for us that we don't know about? Or are you just talking about Vd/$$ numbers?


----------



## SteveCallas

Even if the RL-p18s were only linear for half of their listed xmax and the LMS over all of its, the RL-p18s would still have significantly more linear travel capability. Even if only for only 1/3rd, they would be about equal and still have gobs more headroom and sensitivity. Anyway you slice it, the four RL-p18 option is the better performer. LMS isn't magic.


----------



## Ilkka

SteveCallas said:


> Even if the RL-p18s were only linear for half of their listed xmax and the LMS over all of its, the RL-p18s would still have significantly more linear travel capability. Even if only for only 1/3rd, they would be about equal and still have gobs more headroom and sensitivity. Anyway you slice it, the four RL-p18 option is the better performer. LMS isn't magic.


You DO realize that four RL-p18s would need around 2400L of space?


----------



## jmcomp124

Ilkka said:


> You DO realize that four RL-p18s would need around 2400L of space?


Also, consider how much power it would need. How much?
I can drive a single LMS 5400 with 2 PRs with 2500 watts (one amp). I can fit this in a 250L box and get SPL in the order of 118dB at 16Hz and 120dB above.


----------



## Ilkka

jmcomp124 said:


> Also, consider how much power it would need. How much?
> I can drive a single LMS 5400 with 2 PRs with 2500 watts (one amp). I can fit this in a 250L box and get SPL in the order of 118dB at 16Hz and 120dB above.


Remember that WinISD gives you 1m half-space numbers so you need to subtract 6 dB if you want to compare them to my 2m numbers. Well actually only 3 dB if you are looking at my peak numbers. Peak is 3 dB higher than RMS.


----------



## brucek

> You DO realize that four RL-p18s would need around 2400L of space?


For some reason at the Shack it doesn't seem to be an issue.

The price of admission here is that you can sit inside the box........... :woohoo: 

brucek


----------



## WillyD

SteveCallas said:


> Even if the RL-p18s were only linear for half of their listed xmax and the LMS over all of its, the RL-p18s would still have significantly more linear travel capability. Even if only for only 1/3rd, they would be about equal and still have gobs more headroom and sensitivity. Anyway you slice it, the four RL-p18 option is the better performer. LMS isn't magic.



Thanks for telling me something I already know, that generally speaking multiples always wins. What would I do without you Steve. :dizzy: 

:heehee: 

Except no one claimed that the LMS could "beat" 3 or 4 Rl-p 18s, or that it is magic. So...what are you blabbering on about? I asked if you had any results that we didn't know about because if not, then we still benefit from Ilkka testing a 5400. We can stil here all day long and talk about Vd, sensitivty, linear excursion, but having someone like Ilkka run a relatively full set of tests on an LMS in comparison to other drivers would please a few people here. :reading:

Of course I'd settle for a klippel test from npdang on DIYMobileAudio.


----------



## jmcomp124

Steve,
BTW, that Rambo pic in your avatar, is that an optical illusion?
At first I thought it was a King Cobra seething with hood open and a forked tongue :scared:


----------



## Ilkka

Ilkka said:


> Let's wait until I get a reply from TC-Sounds, ok?


Ok, got their reply. Unfortunately they can't help, so we're on our own. 

Does a single 18" in a 5 cu ft sealed sound good to most? I'm willing to put $200 down if we can pull this through.

Steve, go ahead and start your thread. :arrow:


----------



## jmcomp124

Ilkka said:


> Ok, got their reply. Unfortunately they can't help, so we're on our own.
> 
> Does a single 18" in a 5 cu ft sealed sound good to most? I'm willing to put $200 down if we can pull this through.
> 
> Steve, go ahead and start your thread. :arrow:


Can we do the PRs too? In which case at least 7 cu ft to avoid ringing. Also, if you want sealed, just pull out the PRs and install covers with gaskets. A driver and 2 PRs will cost about $1325. If you can do the 2 PR thing my contribution will be $100, if not, I can do $50. I really hope more people will chip in. It will reduce the burden on those who contribute. Come on guys, let's do this


----------



## jmcomp124

One more suggestion. Start asking enthusiasts who you think will be interested and who you think will be magnanimous to contirbute to the greater good. I am going to bug "TheEar" Arthur who sure will be interested.
onder:


----------



## Ilkka

jmcomp124 said:


> Can we do the PRs too? In which case at least 7 cu ft to avoid ringing. Also, if you want sealed, just pull out the PRs and install covers with gaskets. A driver and 2 PRs will cost about $1325. If you can do the 2 PR thing my contribution will be $100, if not, I can do $50. I really hope more people will chip in. It will reduce the burden on those who contribute. Come on guys, let's do this


Hmm, 7 cu ft is not really optimal sealed nor PR enclosure...

The PR enclosure would need to be around 10 cu ft and to be honest it will be really difficult to get that large enclosure to the testing field unless it's a sono (I live in a second floor apartment).

So if you're asking me, 5 cu ft sealed would be my preference. Even that would be extremely heavy with that ~80 pound LMS driver in it.


----------



## jmcomp124

Ilkka said:


> Hmm, 7 cu ft is not really optimal sealed nor PR enclosure...


Why not? What size do your models say is optimal for a "one size, suit both (sealed and 2 PRs)"?


----------



## Ilkka

jmcomp124 said:


> Why not? What size do your models say is optimal for a "one size, suit both (sealed and 2 PRs)"?


There's no size that's optimal for both. It's either ~5 cu ft or ~10 cu ft.


----------



## jmcomp124

Ilkka said:


> There's no size that's optimal for both. It's either ~5 cu ft or ~10 cu ft.


That's why I chose suboptimal 7. Else we will need 2 boxes. Again the delta in overall end result performance between optimal and suboptimal in this case will be minimal. Within a few dB in terms of Max SPL and other things like distortion etc will also be pretty close. Don't you think so?
This sealed vs ported vs PR argument is as old as the ocean and this small compromise can shed so much light into this subject rather than meaningless endless arguments that sometimes happen in forums based on just theory and subjective opinions. Here we have a chance to really put things on your ruler.


----------



## Ilkka

jmcomp124 said:


> That's why I chose suboptimal 7. Else we will need 2 boxes. Again the delta in overall end result performance between optimal and suboptimal in this case will be minimal. Within a few dB in terms of Max SPL and other things like distortion etc will also be pretty close. Don't you think so?
> This sealed vs ported vs PR argument is as old as the ocean and this small compromise can shed so much light into this subject rather than meaningless endless arguments that sometimes happen in forums based on just theory and subjective opinions. Here we have a chance to really put things on your ruler.


IMO this is a wrong direction. We are not testing the difference between sealed/ported/PR, but LMS vs. other drivers instead.

If I'm testing the sealed/ported/PR difference, I want them all to be optimal. Otherwise the comparison is not as good as it could be.

I know you want me to test the PRs too, but I think we have to compromise a bit. :surrender:


----------



## jmcomp124

Ilkka said:


> IMO this is a wrong direction. We are not testing the difference between sealed/ported/PR, but LMS vs. other drivers instead.
> 
> If I'm testing the sealed/ported/PR difference, I want them all to be optimal. Otherwise the comparison is not as good as it can be.
> 
> I know you want me to test the PRs too, but I think we have to compromise a bit. :surrender:


I leave this to your judgment. Regardless what direction you go, you have my support. :T


----------



## Guest

Ilkka said:


> There's no size that's optimal for both. It's either ~5 cu ft or ~10 cu ft.


Ikka you are THE MAN... Thanks for taking your time to perform these cumbersome tests. **** I am in for donating to the cause :bigsmile: .


----------



## steve nn

> Steve, go ahead and start your thread.:arrow:


Ok cool! One LMS-18" driver test Thread (per Ilkka) coming up Friday afternoon. You know it looks as though we're basically there!


> "TheEar" Arthur who sure will be interested.


 Good idea! I bet Sherv will want to chip in a little also?

Don't tell Ilkka this guys, but when he's done with the 18" sealed version, we'll cleverly get him to take on the PR version if warranted.:heehee:


----------



## jmcomp124

steve nn said:


> Ok cool! One LMS-18" driver test Thread (per Ilkka) coming up Friday afternoon. You know it looks as though we're basically there!
> 
> Good idea! I bet Sherv will want to chip in a little also?
> 
> Don't tell Ilkka this guys, but when he's done with the 18" sealed version, we'll cleverly get him to take on the PR version if warranted.:heehee:


I am with you on this buddy :daydream:


----------



## steve nn

> I am with you on this buddy :heehee:


Yeah this would be a good thing. We know we can take it out with multiple drivers, but just what does this LMS have to offer? 

I just mailed the Chuckster and he'll let Sherv know. We better watch it though!.. If plenty of enthusiasts step up to the plate, Ilkka might be tempted to charge us for BB/MDF and his time:nono: No seriously, it would be way cool to fund the entire project. Anyway, I wonder if we ought to maybe let this Thread get back to it's reg programing.


----------



## jmcomp124

steve nn said:


> Yeah this would be a good thing. We know we can take it out with multiple drivers, but just what does this LMS have to offer?
> 
> I just mailed the Chuckster and he'll let Sherv know. We better watch it though!.. If plenty of enthusiasts step up to the plate, Ilkka might be tempted to charge us for BB/MDF and his time:nono: No seriously, it would be way cool to fund the entire project. Anyway, I wonder if we ought to maybe let this Thread get back to it's reg programing.


Steve,
Where's the new thread :waiting: . Let's get this going ASAP my friend.


----------



## steve nn

> Steve,
> Where's the new thread . Let's get this going ASAP my friend.


I did mention Friday afternoon, but I posted early, quick and dirty just for you.:whew: http://www.hometheatershack.com/for...fers/4652-lms-5400-buy-ilkka-test-thread.html


----------



## Ilkka

I see the ball is already rollin'. :bigsmile:


----------



## SteveCallas

Ilkka said:


> You DO realize that four RL-p18s would need around 2400L of space?


Not really - the comparison was one PR'd LMS 5400 18 vs four RL-p18s. You could seal the RL-p18s and still come out way ahead.



jmcomp said:


> Also, consider how much power it would need. How much?
> I can drive a single LMS 5400 with 2 PRs with 2500 watts (one amp).


SIGNIFICANTLY less power than what you'd have to pump through your single driver sub. Don't forget that adding drivers increases sensitivity. 



Willy said:


> I asked if you had any results that we didn't know about because if not, then we still benefit from Ilkka testing a 5400


We can benefit from Ilkka testing every other driver currently available as well, but if we already know that for the price a certain driver is beaten by other options, why waste time and resources on it? How many 5400 18" projects have we seen to date? One comes to mind.


----------



## mike c

Ilkka, will you be doing the same charts as your previous tests on these subs?
(THD, distortion per component, frequency response, group delay, power compression)


----------



## jmcomp124

SteveCallas said:


> Not really - the comparison was one PR'd LMS 5400 18 vs four RL-p18s. You could seal the RL-p18s and still come out way ahead.
> 
> 
> SIGNIFICANTLY less power than what you'd have to pump through your single driver sub. Don't forget that adding drivers increases sensitivity.
> 
> 
> We can benefit from Ilkka testing every other driver currently available as well, but if we already know that for the price a certain driver is beaten by other options, why waste time and resources on it? How many 5400 18" projects have we seen to date? One comes to mind.


I had asked this question if there was any driver that matched or beat the LMS5400 in the USA (under $1000) and the answer was no and it was worth the wait. You say otherwise. When you say one PR
d LMS5400, do you mean 1 LMS5400 and 2 PRs?
Compare a single sealed LMS 5400 with 2 PRs to the RL-P18s you propose. Assume a 10 cu ft(About 290 L) box with Quad (2 opposing pairs in a sealed box). If you can be specific on how much amp power this would need, how much would the drivers and amp costs and compare them to the driver/PR and amp cost of the LMS5400, and show that the p-18s will come ahead then that would be useful.

The point is not how multiple RL-P18s compare to an LMS 5400 but rather, we see the LMS 5400 as a very unique product in this marketplace. WIth the linearity, power and convenience of fitting in a small box, it looks very attractive. The reason why I think there are not that many projects on this driver is 1st, because of cost and 2nd the availability. So hence the interest in this thread on TC sounds flagship product especially after seeing how well their TC2K performs. If Ilkka's measurements prove that all that is claimed about htis driver is true, then we have a winner that many who crave for the best will go after. I do not believe this is a waste of time and resource. Just my $0.02 for what it is worth. 
Thanks,
-Jai


----------



## jmcomp124

Ilkka said:


> I see the ball is already rollin'. :bigsmile:


The thread got moved. Where is it now? I am not that familiar with all the classes.


----------



## brucek

> The thread got moved. Where is it now?


The thread was moved to SubWoofer Tests where Ilkka is the moderator. 

brucek


----------



## SteveCallas

jmcomp said:


> When you say one PRd LMS5400, do you mean 1 LMS5400 and 2 PRs?


No, I'm pretty sure you'd need more than two PRs - even if 18" and high excursion - to be able to extract all the performance from the 18" 5400. Mark is using two 18" PRs for his BMF if I am not mistaken, and that uses a 15" driver.



jmcomp said:


> Compare a single sealed LMS 5400 with 2 PRs to the RL-P18s you propose. Assume a 10 cu ft(About 290 L) box with Quad (2 opposing pairs in a sealed box). If you can be specific on how much amp power this would need, how much would the drivers and amp costs and compare them to the driver/PR and amp cost of the LMS5400, and show that the p-18s will come ahead then that would be useful.


That's what WinISD and the internet are here for  



jmcomp said:


> The point is not how multiple RL-P18s compare to an LMS 5400 but rather, we see the LMS 5400 as a very unique product in this marketplace. WIth the linearity, power and convenience of fitting in a small box, it looks very attractive


That's fine. I think when one takes a glance at the diy sub projects completed on this forum and others though, performance per dollar is the main objective. Small is a compromise.


----------



## Mark Seaton

jmcomp124 said:


> That's why I chose suboptimal 7. Else we will need 2 boxes. Again the delta in overall end result performance between optimal and suboptimal in this case will be minimal. Within a few dB in terms of Max SPL and other things like distortion etc will also be pretty close. Don't you think so?
> This sealed vs ported vs PR argument is as old as the ocean and this small compromise can shed so much light into this subject rather than meaningless endless arguments that sometimes happen in forums based on just theory and subjective opinions. Here we have a chance to really put things on your ruler.


:rofl:

Jmcomp thinks that Ilkka's measurement session will give clear and obvious answers to settle these questions of the ages. :joke:


----------



## Kevin_Wadsworth

SteveCallas said:


> Mark is using two 18" PRs for his BMF if I am not mistaken, and that uses a 15" driver.


Three 18" PR's, at least as of the last design update. Although one is in fromnt of the driver and only two are in the box.


----------



## jmcomp124

Mark Seaton said:


> :rofl:
> 
> Jmcomp thinks that Ilkka's measurement session will give clear and obvious answers to settle these questions of the ages. :joke:


Hey Mark, 
Yeah, it is :rofl: , I don't think it will settle, but I do think it will shed more light .
I am :waiting: for your thoughts on the PR question I had earlier stemming from this comment

"A resonant structure with no direct control loop to the stimulation signal is by definition a source of distortion. " Post# 185.


----------



## jmcomp124

SteveCallas said:


> No, I'm pretty sure you'd need more than two PRs - even if 18" and high excursion - to be able to extract all the performance from the 18" 5400. Mark is using two 18" PRs for his BMF if I am not mistaken, and that uses a 15" driver.
> 
> 
> That's what WinISD and the internet are here for
> 
> 
> That's fine. I think when one takes a glance at the diy sub projects completed on this forum and others though, performance per dollar is the main objective. Small is a compromise.


Yes, at least 2 PRs are needed to keep them in safe limits. Yes, I did a quick model. According to what I see, your proposal needs a very large box. I agree that performance per dollar is the main objective, but size cannot be ignored. I would like to see other woofers like you mentioned, measured too, but we need to start somewhere . 

In a way I think Ilkka set my expectation too high with all the cool DIY stuff he is measuring now. I still think this LMS 5400 measurement is daydreaming, but we will see. Thanks for your inputs.


----------



## Mark Seaton

jmcomp124 said:


> Hey Mark,
> Yeah, it is :rofl: , I don't think it will settle, but I do think it will shed more light .
> I am :waiting: for your thoughts on the PR question I had earlier stemming from this comment
> 
> "A resonant structure with no direct control loop to the stimulation signal is by definition a source of distortion. " Post# 185.


An answer to that is pretty off topic and probably belongs in your project thread. I'll give the short response here.

Most components in a loudspeaker system are resonant objects. The maker of the comment feels everything needs feedback correction. Feedback correction can be very useful and is something I am fond of, depending on how it is used/implemented.

All of the systems referred to are simply higher order systems. Each can have non-linearities. I'm not sure if the maker of the comment is just referring to the non-linearities in operation, or the added time shifting of the higher order systems. If the time smearing is viewed as distortion, then all systems have this distortion, where higher order systems just add more of it. I suspect he's referring to being able to electronically linearize the operation of a port or PR, but that depends on the correction used. Any non-linearity in a port or PR will be reflected in the impedance, and could therefore be compensated for to some degree. Of course it doesn't have much bearing on your project since you aren't using any sort of feedback.


----------



## WillyD

> We can benefit from Ilkka testing every other driver currently available as well, but if we already know that for the price a certain driver is beaten by other options, why waste time and resources on it? How many 5400 18" projects have we seen to date? One comes to mind.


Where does it end? Almost every driver can be 'beaten' by other options for the price if one goes with multiples of lesser drivers, honestly. That is a ridiculous arguement against the testing of various drivers. Tell Ilkka he shouldn't have bothered testing the Tumult, since A) it can't be bought new anymore and B) We 'already know it could've been beat' for less money by other options. And that is just one example. Why bother with the TC-2000? One can get three Dayton DVC subs for the same price. It could go on...and on...:sarcastic: 

How many? Not many, and that is due to A) availability and B) price. Most people don't spend $875 or more on their entire sub (I am referring to DIYers) but for someone who has a specific need such as high quality/high output in a limited space, I don't see why a driver like the LMS should be so easily written off.


----------



## Ilkka

mike c said:


> Ilkka, will you be doing the same charts as your previous tests on these subs?
> (THD, distortion per component, frequency response, group delay, power compression)


Yes, naturally.  Just give me some time since I have a lot of data to go through.


----------



## Ilkka

Kevin_Wadsworth said:


> Three 18" PR's, at least as of the last design update. Although one is in fromnt of the driver and only two are in the box.


Only two of them are producing the low frequencies. The front PR is for upper bass frequencies. And I could be wrong, but I think they have a bit less linear excursion than TC-Sounds' PRs.

Two high excursion PRs per one active isn't that bad idea. It's about the same as using a 6" port with a 15" driver. Yes there will be some compression around the tuning frequency, but not much.


----------



## steve nn

Everyone that has posted a pledge, can I bother you to re-post your pledge over in this Thread for simplicity sake as to keep track. Thanks guy's. Back to reg programing.

http://www.hometheatershack.com/for...lms-5400-buy-ilkka-test-thread.html#post36042


----------



## SteveCallas

Willy said:


> Tell Ilkka he shouldn't have bothered testing the Tumult, since A) it can't be bought new anymore and B) We 'already know it could've been beat' for less money by other options. And that is just one example. Why bother with the TC-2000? One can get three Dayton DVC subs for the same price.


The Tumult is in widespread use, it makes sense to test it. I'm not entirely sure 3 Dayton DVC 15s could do what a TC 2000 could. I'm positive four RL-p18s could best a LMS 5400 18.


----------



## Ilkka

SteveCallas said:


> I'm positive four RL-p18s could best a LMS 5400 18.


I don't think there's even a question about it? Even two of them would give more max SPL.

But the difference is that four RL-p18s will need lots of more volume than a single LMS. You can't assume that everyone will accept a huge subwoofer. I for one can not think of using anything larger than 5-6 cu ft. I know I have to compromise but that's life.


----------



## WillyD

SteveCallas said:


> The Tumult is in widespread use, it makes sense to test it. I'm not entirely sure 3 Dayton DVC 15s could do what a TC 2000 could. I'm positive four RL-p18s could best a LMS 5400 18.


So widespread use despite it now being unavailable makes it more worthy? I disagree. It isn't exactly easy to find used tumults these days anyway. And of course it is widespread use, it was available years ago. Keep in mind it wasn't cheap either, ~$600. If you compare the Tumult and the 5400 and what they offer I don't see how one could consider the 5400 overpriced, unless they also consider the Tumult overpriced (which you probably do, so why bother). 

And why aren't you sure that 3 Dayton DVC 15s could do what a TC-2000 could? We're talking about 7.30236 liters (three DVCs) of linear displacement vs 4.5136 liters (TC-2K). And then you have the fact that three drivers are sharing the load instead of one...so explain how the DVCs can't do it, but the Rl-p 18s can? 

And still, stop comparing four Rl-p 18s to the LMS-5400. Even three would cost over $100 more shipped to your door than a single 5400, and they'd also require significantly larger boxes than the 5400 (something like 150liters to 90 liters if both have the same Q of .65). And like Ilkka said, even two would offer more max SPL. This isn't an apples to apples comparison. And you mustn't bother with the "don't have the size, you must compromise" bit, I've read it enough. :yes:

So I don't really know why you keep trying to beat it into our heads when none of us are arguing with you about 2, 3, or 4 Rl-p 18s beating out an LMS-5400 w.r.t SPL.


----------



## Ilkka

WillyD said:


> And still, stop comparing four Rl-p 18s to the LMS-5400. Even three would cost over $100 more shipped to your door than a single 5400, and they'd also require significantly larger boxes than the 5400 (something like 150liters to 90 liters if both have the same Q of .65).


Do we have the same parameters? WinISD gives ~205L for the RL-p18 D2 and 271L for the D4. LMS-5400 wants 89L. All having Q of ~0.7.


----------



## WillyD

Ilkka said:


> Do we have the same parameters? WinISD gives ~205L for the RL-p18 D2 and 271L for the D4. LMS-5400 wants 89L. All having Q of ~0.7.


I was using Unibox, with a Qa of 20. 

Fs	20.71	Hz
Re	3.74	Ohm
Qms	4.54	
Qes	0.48	
Sd	1188.0	cm2
Vas	314.2	l
Xmax peak	27.40	mm
Le	3.30	mH
Le2	3.32	mH
Re2	7.63	Ohm

But either way, the Rl-p requires a significantly larger box.


----------



## Ilkka

WillyD said:


> I was using Unibox, with a Qa of 20.
> 
> Fs	20.71	Hz
> Re	3.74	Ohm
> Qms	4.54
> Qes	0.48
> Sd	1188.0	cm2
> Vas	314.2	l
> Xmax peak	27.40	mm
> Le	3.30	mH
> Le2	3.32	mH
> Re2	7.63	Ohm
> 
> But either way, the Rl-p requires a significantly larger box.


Hmm, Qa=20 and Ql=15 give me 214L with Q=0.65.


----------



## SteveCallas

Ilkka said:


> But the difference is that four RL-p18s will need lots of more volume than a single LMS


Again, not really. This comparison came about because of the cost associated with a PRd 5400 18". Four sealed RL-p18s all in one box on opposing sides could still be a fair amount smaller than a properly PRd 5400 18" with a ~14hz tune. EQ can always be used to flatten out the sealed's low end - while I don't care for that approach, it would still outperform the single PRd 5400 18.



Willy said:


> So widespread use despite it now being unavailable makes it more worthy?


Absolutely. People want to know what they have in their hands. With the LMS, I only know of one guy who has one, and even if it performs pretty well, very few are gonna plop down $900 for a driver. So who'd really benefit from testing it? Are you gonna buy one if it tests well? I think the requests to test it are just so some people can "oooh" and "ahhh" at it. Nothing wrong with that, but more use can be gotten out of testing more popular drivers. There would actually be more use in testing the DVC 15 than the LMS 5400 me thinks, based on how many are in circulation.



> And why aren't you sure that 3 Dayton DVC 15s could do what a TC-2000 could? We're talking about 7.30236 liters (three DVCs) of linear displacement vs 4.5136 liters (TC-2K). And then you have the fact that three drivers are sharing the load instead of one...so explain how the DVCs can't do it, but the Rl-p 18s can?


We can assume the RL-p18 is using (at the least) a pretty linear motor based on several cues. We don't know what to expect from the DVC. Three DVCs may have more air movement capability than one TC 2000, but we don't know if it would be as clean at given output levels. 



> And still, stop comparing four Rl-p 18s to the LMS-5400. Even three would cost over $100 more shipped to your door than a single 5400, and they'd also require significantly larger boxes than the 5400 (something like 150liters to 90 liters if both have the same Q of .65). And like Ilkka said, even two would offer more max SPL. This isn't an apples to apples comparison


You have to factor in something like 3 or 4 high excursion PRs to get full usefulness out of the LMS 5400 18", that's why I compared it to 4 RL-p18s to begin with. Otherwise you are no better than just porting it for free. The 4 RL-p18s don't need a naturally low Q, EQ is almost mandatory with sealed anyway, just LT it. 

$ = $ is ALWAYS an apples to apples comparison.


----------



## Ilkka

SteveCallas said:


> Again, not really. This comparison came about because of the cost associated with a PRd 5400 18".


I though we were comparing sealed LMS to sealed RL-p. Sorry about that. 



> Four sealed RL-p18s all in one box on opposing sides could still be a fair amount smaller than a properly PRd 5400 18" with a ~14hz tune.


Not really. 5400 will work in 250-300L while that's way too small for four RL-p18s. Q would be around 1. You would need a lot of power in that kind of box. Around 600L would be the smallest usable.


----------



## brucek

> Do we have the same parameters? WinISD gives ~205L for the RL-p18 D2 and 271L for the D4. LMS-5400 wants 89L. All having Q of ~0.7.


Yep, for all three...............


LMS-5400 sealed with 2500 watts...








brucek


----------



## Guest

Wow that was alot of reading to get through this thread... I happened to wonder over from one of the "other" forums and have thoroughly enjoyed the discussion here. Ilkka, I would like to thank you for putting so much time in gathering and analyzing this data for all of us to benefit 


I have a couple questions regarding the SVS-PB12 NSD. Was it able to produce the full sweep down to 16hz w/o port chuffing? I was honestly really surprised that it kept up with VTF3-MK3 w/ turbo down to 16hz especially considering it has only one 4" port.

I thought I had my choice made w/ the V3.3 but you may have throw a wrench into my plans


----------



## WillyD

> Again, not really. This comparison came about because of the cost associated with a PRd 5400 18". Four sealed RL-p18s all in one box on opposing sides could still be a fair amount smaller than a properly PRd 5400 18" with a ~14hz tune. EQ can always be used to flatten out the sealed's low end - while I don't care for that approach, it would still outperform the single PRd 5400 18.


That couldn't be more wrong. A properly designed PR LMS-5400 18" sub wouldn't need to be more than 250l net. Four RL-p 18s sealed would need, by my sims, _at least_ 700liters just to get to a Q or .7 Fair amount smaller? lol, good one Steve. :coocoo: 

And I don't know of many folks who consider cramming drivers in sealed boxes with a high Q by choice, but Bosso is one of those folks. Almost everyone else out there prefers to get the lowest natural Q possible. 



> We can assume the RL-p18 is using (at the least) a pretty linear motor based on several cues. We don't know what to expect from the DVC. Three DVCs may have more air movement capability than one TC 2000, but we don't know if it would be as clean at given output levels.


How can we assume this? Please provide me with these cues, thanks. :sneeky: 

You're sitting here repeating the fact that multiple Rl-p 18s move much more air than a single LMS-5400, but when I suggest three DVCs (which also move a a good bit more air) for the same price of a TC-2000, you say the comparison doesn't have merit. Craziness. It goes both ways. 

Again, if you have some data that we don't know about which supports your claims (not the more air=more spl, but linearity), please share it. 



> You have to factor in something like 3 or 4 high excursion PRs to get full usefulness out of the LMS 5400 18", that's why I compared it to 4 RL-p18s to begin with. Otherwise you are no better than just porting it for free. The 4 RL-p18s don't need a naturally low Q, EQ is almost mandatory with sealed anyway, just LT it.


You were the one that started this PR vs Sealed argument w.r.t the 5400/Rl-p, which is crazy as you well know. If you're going to compare driver to driver, it makes MUCH more sense to use sealed in both comparisons. This you can't argue. 

And yes, like you said, you are no better than just porting it for free, but this is pointless when consider people who can't put 500-600 liter enclosures in their rooms. No, I don't have this problem, some do, and yes, if they don't have the size they must compromise.

Again, I really don't know why we are discussing this. You and I don't know anything about these drivers other than their specs or what users have said. Those aren't exactly the best benchmarks to compare performance, which is why I'd prefer some real world testing. 

I don't know why I bother. This is all quite irrelevant to me seeing as I will never purchase a driver that is so expensive, simply because I don't have the means and my listening needs don't require one. I too would buy four Rl-p 18s before an LMS-5400 and PRs, but I wouldn't cram them into a box, I'd do IB just so there wouldn't be gigantic tubes taking up space in the new small room where my HT will be...and the Q would naturally be nice and low. Less power needed, less EQ needed = win. Or better yet...an SLLT to get even more low end output and significantly less leakage of sound throughout the attic. 

Now, this upcoming SDX15 driver, that is another story. I have two extra sonotubes that wouldn't mind two of these...LLT style....:devil:

Lets just drop this useless discussion. Word? :whistling:


----------



## Ilkka

Even though I self participated too, I have to ask you two, Steve and Willy, to take that discussion somewhere else.

Thank you.


----------



## Ilkka

CupCak3 said:


> Wow that was alot of reading to get through this thread... I happened to wonder over from one of the "other" forums and have thoroughly enjoyed the discussion here. Ilkka, I would like to thank you for putting so much time in gathering and analyzing this data for all of us to benefit
> 
> I have a couple questions regarding the SVS-PB12 NSD. Was it able to produce the full sweep down to 16hz w/o port chuffing? I was honestly really surprised that it kept up with VTF3-MK3 w/ turbo down to 16hz especially considering it has only one 4" port.
> 
> I thought I had my choice made w/ the V3.3 but you may have throw a wrench into my plans


No, naturally the SVS PB12-NSD will have more port noise around the tuning frequency due only having single 4" port compared to HSU's dual ports. But if didn't have enough port noise to exceed the CEA 2010 distortion limit.

I would definitely wait for the full results before making any decisions based on these tests. These CEA 2010 numbers are just a part of the equation, not the full picture.


----------



## Guest

Ilkka said:


> No, naturally the SVS PB12-NSD will have more port noise around the tuning frequency due only having single 4" port compared to HSU's dual ports. But if didn't have enough port noise to exceed the CEA 2010 distortion limit.
> 
> I would definitely wait for the full results before making any decisions based on these tests. These CEA 2010 numbers are just a part of the equation, not the full picture.


Sounds fair enough. I'll be anxiously awaiting


----------



## bossobass

> And I don't know of many folks who consider cramming drivers in sealed boxes with a high Q by choice, but Bosso is one of those folks. Almost everyone else out there prefers to get the lowest natural Q possible.


To clarify...I prfer the smallest box that stays within the 5% rule of volume vs displacement. This offers the best balance of excursion protection, subwoofer size-to-output and excursion linearity.

There is no need to endlessly model the driver in various sized boxes. Use the 5% formula, build and test the sub, nearfield and configure the L/T accordingly. You'll get the most accurate end result this way.

Examine the effect of the L/T at the natural corner of a higher Q system and you'll see effective use of the free lunch boost the high Q offers. The L/T will actually reduced the input signal at that point before adding any boost. In the so-called music BW, this reduction of input power adds headroom.

Below 20 Hz, there is a 'loss' of efficiency, but that isn't a bad thing unless you like the added distortions of a non-linear stroke in trade for a couple of dB more output in that range. It makes much more sense to increase the number of subs, especially since you have huge economy of space savings to play with.

Regarding the Tumult and Tumult MKII, they still remain the king of subwoofer drivers. Since I have four of each, I'm not suffering an availability problem, and I'm happy to see Ilkka test one.:jump: 

Bosso


----------



## WillyD

I apologize Bosso, you were just the first person that popped into my head w.r.t smaller sealed boxes. :bigsmile:

And still remain the king? You are so confident..or biased. :mooooh:

And I apologize Ilkka, for messing with the flow of the thread. Any updates with the TC-2000s?


----------



## bossobass

WillyD said:


> I apologize Bosso, you were just the first person that popped into my head w.r.t smaller sealed boxes. :bigsmile:
> 
> And still remain the king? You are so confident..or biased. :mooooh:
> 
> And I apologize Ilkka, for messing with the flow of the thread. Any updates with the TC-2000s?


No apologies necessary, my friend. It was an accurate statement.

I am confident in the superiority of a properly designed and built 15" XBl^2 uber-driver because I've tested several of them against all comers (except the Acoupower 15", which looked awfully good on paper, but disappeared before I could get a pair. I still occasionally lament the ****-poor treatment Carlos received on line).

The XBl^2 motor and composite Kevlar/paper cone (I saw Dan stand on one with his full weight...don't try this with an aluminum cone) make for the cleanest reproduction at the largest excursion of any driver I've tested. The downside of power handling disparity against a huge overhung has not seemed to be an issue in the years I've coupled them with very large power plants. 

I recall only one fused coil being reported over the years by Brian Bunge, who applied 2400 watts and an L/T and took one of his Tumults to the land of magic smoke. Well, that's just a bit over it's rating:surrender: 

I think Ilkka said earlier that the tested Tummy was driven with 600 watts per coil? I believe a Tumult will easily safely handle a couple more dB of input power, so we can do the math. 

I'll be surprised to see any other 15" sub best the Tumult-based sub's overall performance, but then again...that's why I'm here:hail: 

Bosso


----------



## WillyD

> don't try this with an aluminum cone


Right on, that is definitely a weak point of some of the TC drivers IMO. I suppose that is why the 3000 and 5series drivers have Ti cones. :nerd: 

I really wish they'd offer these cones as an option, granted I don't know how strong they are, but I bet they are less prone to dents/etc than the Alu cones and they look really nice. 



> I think Ilkka said earlier that the tested Tummy was driven with 600 watts per coil? I believe a Tumult will easily safely handle a couple more dB of input power, so we can do the math.


Yeah, I kind of wish it had been tested with the same ~2000W amp he used with some other tests. 



> but then again...that's why I'm here


Indeed! 

He'll have to acquire one or more of these upcoming 15" XBL^2 drivers available at creativesound.ca I dunno if they are up to your Tumult standards, but check out that price.


----------



## bobgpsr

bossobass said:


> I recall only one fused coil being reported over the years by Brian Bunge, who applied 2400 watts and an L/T and took one of his Tumults to the land of magic smoke.


I blew out a 15" Tumult MKII with too may watts while watching Children Of Men on HD DVD:










The terrorist explosion early in the movie did it. :scared: Overpowered the 15D2 Tumult I guess with effective 1400 watts with a bridged Mackie M1400i pro amp driving 4 ohms (the two Tumult 2 ohm vc's in series). :nono: Warning do not do this.


----------



## mike c

Ilkka said:


> Yes, naturally.  Just give me some time since I have a lot of data to go through.


thanks Ilkka, very much interested in the SVS SB12 and Monitor Audio RSW12 results


----------



## bossobass

bobgpsr said:


> I blew out a 15" Tumult MKII with too may watts while watching Children Of Men on HD DVD:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> The terrorist explosion early in the movie did it. :scared: Overpowered the Tumult I guess with effective 1400 watts with a bridged Mackie M1400i pro amp driving 2 ohms (the two Tumult vc's in parallel). :nono: Warning do not do this.


Hmmm, the two VCs in parallel would be 1 ohm, no? I wasn't aware that there were ever any D4 Tumults for sale??

I have tested a 1200 watt 1XTumult and I can't see that much power doing that much damage with that source material?

Bosso


----------



## Chrisbee

Sorry to jump in here but I'd day that "Children of Men" is a real sub wrecker! The gunfire explosions at the end of the film were reference quality when I watched this film for the first time last night. I have never seen so much cone movement or physically felt blasts like this before. The early explosion had us ducking but wasn't as serious as those at the end of the film. I have no idea if I was watching in Dolby or DTS as the hire DVD was so thoroughly screwed up with protection it wouldn't even let me see the menu! Somebody here needs more woofage not more kiloWatts. :devil:


----------



## Ilkka

WillyD said:


> And I apologize Ilkka, for messing with the flow of the thread. Any updates with the TC-2000s?


I've been contacting TC-Sounds, but they can't really do much. We will test one of my drivers in that 90L box just to be sure. I will also take a few impedance responses.

Sadly we had some more drama today. :sarcastic:


----------



## Ilkka

WillyD said:


> Yeah, I kind of wish it had been tested with the same ~2000W amp he used with some other tests.


Yeah, we though about that but then again the owner wanted to see how his amp was doing. Maybe we'll measure it again some with more bigger amp.

And that Yamaha amp was around 2x600W RMS, 2x800W peak. So the difference wasn't that large. 1-2 dB max.


----------



## Ilkka

mike c said:


> thanks Ilkka, very much interested in the SVS SB12 and Monitor Audio RSW12 results


I haven't measured a Monitor Audio RSW12? Only its little brother, BRW10.


----------



## Blaser

Ilkka said:


> Sadly we had some more drama today. :sarcastic:


 Drama?!! What is happening to you Ilkka? Is this testing season accompanied by some lack of luck???:rubeyes:


----------



## Ilkka

blaser said:


> Drama?!! What is happening to you Ilkka? Is this testing season accompanied by some lack of luck???:rubeyes:


Bad luck or bad quality woofers.


----------



## WillyD

Ilkka said:


> Yeah, we though about that but then again the owner wanted to see how his amp was doing. Maybe we'll measure it again some with more bigger amp.
> 
> And that Yamaha amp was around 2x600W RMS, 2x800W peak. So the difference wasn't that large. 1-2 dB max.


:T


----------



## Manic Miner

Ilkka said:


> Bad luck or bad quality woofers.



Please give us some gossip :bigsmile: 

I've spent the ENTIRE day pushing my PB12-Plus around my living room and measuring the FR with REW, only to find out that the spot where it was to begin with was the best :hush: So I could use some entertainment.


----------



## bobgpsr

bossobass said:


> Hmmm, the two VCs in parallel would be 1 ohm, no? I wasn't aware that there were ever any D4 Tumults for sale??


You are so right. I went downstairs and checked. The amp was in bridge configuration but the voice coils were in series (had to cut the dual banana plugs to do a series connection at the dual banana jack connection on the back of the subwoofer enclosure). This was covered up and I forgot what I did -- at least I did not try to drive 1 ohm. Yes the Tumult is a 15D2. Need to get it re-coned now.  Thinking about buying a new piece of baltic birch and trying a RL-p18 in its place. Triple layer the front baffle. The question is will the two 18" PR's be enough? Need to do some Unibox modeling.

I edited my previous post. Thanks for the correction Bosso.


----------



## Ilkka

Manic Miner said:


> Please give us some gossip :bigsmile:
> 
> I've spent the ENTIRE day pushing my PB12-Plus around my living room and measuring the FR with REW, only to find out that the spot where it was to begin with was the best :hush: So I could use some entertainment.


I won't share it yet but here's the updated spreadsheet. The 20-39PC+ had the newest 12.3 driver and its results will be comparable to the PB12-Plus.

Added:
HSU VTF-3 MK3 ME
SVS 20-39PC+ 12 Hz
SVS 20-39PC+ 16 Hz
SVS 20-39PC+ 20 Hz
XTZ 99 W12 MO
XTZ 99 W12 ME

MO = maximum output/2 ports open
ME = maximum extension/1 port open


----------



## Manic Miner

Thanks Illka. That some amazing numbers for the XTZ in the highest frequencies. Looks like there is no point for us europeans to buy the MBM as long as the XTZ can be had for less


----------



## brucek

> Yes the Tumult is a 15D2. Need to get it re-coned now.


hehehe, I see that they would consider a trade in on a broken Tumult for the soon to be released Creative Sounds SDX15 XBL^2 15" driver. 

It says in part: _Trade-in Program being considered!

If you have a non-working 15" Adire Brahma or Tumult and would be interested in trading it in for an SDX15 at a discount please send us an email._

I modelled the new 30mm xmax XBL^2 15" driver and it seems OK... what do I know......

brucek


----------



## Ilkka

Manic Miner said:


> Thanks Illka. That some amazing numbers for the XTZ in the highest frequencies. Looks like there is no point for us europeans to buy the MBM as long as the XTZ can be had for less


Yeah, it's a great mid bass woofer, but the frequency response drops quickly below 50 Hz. Very similar to the MBM-12 actually.


----------



## Manic Miner

Ilkka said:


> Yeah, it's a great mid bass woofer, but the frequency response drops quickly below 50 Hz. Very similar to the MBM-12 actually.


I sometimes forget that the CEA numbers do not tell the full story, I look forward to your full report 

Something that caught my eye is that the PC+ has more clean output @20hz in 16hz mode than in 20 hz mode. Any idea why? Ah wait, I think I know myself. The PC model has a higer tuning point than the PB, so 20hz mode is not really 20hz tune, but a bit higher. And if the same goes for the 16hz mode that would explain the numbers?


----------



## Ilkka

Manic Miner said:


> I sometimes forget that the CEA numbers do not tell the full story, I look forward to your full report
> 
> Something that caught my eye is that the PC+ has more clean output @20hz in 16hz mode than in 20 hz mode. Any idea why? Ah wait, I think I know myself. The PC model has a higer tuning point than the PB, so 20hz mode is not really 20hz tune, but a bit higher. And if the same goes for the 16hz mode that would explain the numbers?


That's the reason, but IIRC PC and PB models should be pretty much identical when it comes to tuning frequencies. 20 Hz mode is around 21 Hz and 16 Hz mode is around 17.5 Hz.


----------



## mike c

Ilkka said:


> I haven't measured a Monitor Audio RSW12? Only its little brother, BRW10.


oh right. sorry, was thinking of something else


----------



## Kermie

How would a HSU MBM-12 work with the SVS PB-12 Plus/2?


----------



## jmcomp124

bobgpsr said:


> I blew out a 15" Tumult MKII with too may watts while watching Children Of Men on HD DVD:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> The terrorist explosion early in the movie did it. :scared: Overpowered the 15D2 Tumult I guess with effective 1400 watts with a bridged Mackie M1400i pro amp driving 4 ohms (the two Tumult 2 ohm vc's in series). :nono: Warning do not do this.


When something like this happens, I always wonder if a model could have prevented this.
When you designed your sub, with the rated input power, Pe, did your model show that your driver is within safe excursion?
Thanks,
-Jai


----------



## Mark Seaton

Jai, From that picture we have no idea of what the failure mode was or what caused it. The only clear thing is that the dustcap popped off.

If you do some real homework on the matter you will also find that thermal specs for a raw driver are really fuzzy. Maximum power handling is inversely proportional to duration. So do you want the 0.5 sec, 30 second, 10 minute, 2 hour, or 24 hour rating? :scratchhead: 

Oh yeah, and with what input signal did you want that power rating? Over what bandwidth, and in what specific box? Box design and bandwidth or frequency content of the test signal make for significant differences in both mechancial (excursion) and power input limits (heat in the voice coil).

All power tests tell you is that the device survived some specific input signal in some mounting condition over some duration.


----------



## bobgpsr

jmcomp124 said:


> When something like this happens, I always wonder if a model could have prevented this.
> When you designed your sub, with the rated input power, Pe, did your model show that your driver is within safe excursion?


I used the spec for the 15D2 of 1000w in Unibox.










The model showed hitting the red excursion max line just above tuning (14 Hz). I will sheepishly :duh: admit that I went 400w over the design with amplifier drive capability. The real problem was that my audio level calibration was off (due to a firmware upgrade in the HD DVD player).

I did set the Mackie's fine adjustable high pass filter to approx 16 Hz as a result of past testing and for what the model shows happens with excursion below the tuning.

Bob


----------



## jmcomp124

Mark Seaton said:


> Jai, From that picture we have no idea of what the failure mode was or what caused it. The only clear thing is that the dustcap popped off.
> 
> If you do some real homework on the matter you will also find that thermal specs for a raw driver are really fuzzy. Maximum power handling is inversely proportional to duration. So do you want the 0.5 sec, 30 second, 10 minute, 2 hour, or 24 hour rating? :scratchhead:
> 
> Oh yeah, and with what input signal did you want that power rating? Over what bandwidth, and in what specific box? Box design and bandwidth or frequency content of the test signal make for significant differences in both mechancial (excursion) and power input limits (heat in the voice coil).
> 
> All power tests tell you is that the device survived some specific input signal in some mounting condition over some duration.


I would choose the 30 seconds, unless Bob decided on some insane sine wave test which I don't think he did (he was playing the terrorist explosion scene from Children of Men). 


"All power tests tell you is that the device survived some specific input signal in some mounting condition over some duration"

From your quote, I think that's the best an analytical model can do, is just that (maybe slightly better if they were backed up with more funds) and for more we would want simulations or real world prototypes.

I was curious to see how strictly Bob followed the model recommendations. It appears he made some compromises. I think that is a good lesson to learn.
Red means stop, if you/someone else doesn't notice red, "brace" :scared:


----------



## Mark Seaton

Jai, 

I think you selectively skimmed past the point about the impact of the enclosure type/size and the bandwidth of the input signal. In specific cases these changes could result in 4-10 fold differences in tolerated input signal.

Just some food for thought as everyone gets their panties in a bunch over power ratings.


----------



## jmcomp124

Mark Seaton said:


> Jai,
> 
> I think you selectively skimmed past the point about the impact of the enclosure type/size and the bandwidth of the input signal. In specific cases these changes could result in 4-10 fold differences in tolerated input signal.
> 
> Just some food for thought as everyone gets their panties in a bunch over power ratings.


I agree with you Mark. There are always exceptions and specific cases. My point is that whatever guidelines the model suggests, it is best to give it some serious consideration. That's all I am saying. 
You are alluding, no matter how carefully you model, there are always cases that could cause such things to happen so don't take it as written on stone. I agree.


----------



## ssabripo

Ilkka said:


> I won't share it yet but here's the updated spreadsheet. The 20-39PC+ had the newest 12.3 driver and its results will be comparable to the PB12-Plus.
> 
> Added:
> HSU VTF-3 MK3 ME
> SVS 20-39PC+ 12 Hz
> SVS 20-39PC+ 16 Hz
> SVS 20-39PC+ 20 Hz
> XTZ 99 W12 MO
> XTZ 99 W12 ME
> 
> MO = maximum output/2 ports open
> ME = maximum extension/1 port open


NICE....looks like the measly TC2K in a vented sonosub is spanking the field, at least in terms of SPL (with CEDIA boundaries). I wonder how an 18" avalanche XBL^2 in a 650L sonosub tuned to 12hz, would fare :nerd: 

anyone wants to start a "Shipping Trust Fund" to send one to Ilkka for testing?? raying:


----------



## steve nn

> anyone wants to start a "Shipping Trust Fund" to send one to Ilkka for testing??


Hey Sherv! I mailed the Chuckster letting him know about what we have going on over here and asked him to let you know since I lost your address in the move. I dunno if your still interested, but you have had plenty interest in the past regarding the LMS-5400. I'm also very interested to see how the new 18" RLP would fare out?

As a reminder, if anyone that has stated a interest in contributing many posts/pages back in this Thread, I'll need you to re-post as to keep things simple. I'll give my $$ away, but save my time for DIY, not sifting through posts.:reading: You can also mail Ilkka or myself and I'll ad it to the list.
http://www.hometheatershack.com/forums/subwoofer-tests/4652-lms-5400-buy-ilkka-test-thread.html


----------



## ssabripo

man, you are trying to get me divorced for sure, aint cha?!!!!


----------



## Ilkka

ssabripo said:


> NICE....looks like the measly TC2K in a vented sonosub is spanking the field, at least in terms of SPL (with CEDIA boundaries). I wonder how an 18" avalanche XBL^2 in a 650L sonosub tuned to 12hz, would fare :nerd:
> 
> anyone wants to start a "Shipping Trust Fund" to send one to Ilkka for testing?? raying:


Sherv! Good to see you here. 

Yeah, it would be fun to see how your sono would fare. But I don't think we have to start a shipping trust fund. I know there is at least one or two LARGE sonosubs in the builds here in Finland as we speak. Next measurement session should be even more interesting. :rubeyes:


----------



## steve nn

> man, you are trying to get me divorced for sure, aint cha?!!!!


Oops!.. I forgot:duh: Well it was all your yak about the 54 that got me going, so buck up my friend.:boxer: OK.. but Think of all the money your $aving by living through Ilkka, she's got to like that? ha ha


----------



## jmcomp124

Ilkka,
Building a 7.5 cu ft box suitable for both PR and Sealed sub testing is still not a bad idea.
Look at this http://www.tcsounds.com/lms5400.htm
Large box low extension is a good candidate for sealed subs. Gracious, it is a good candidate for PRs too.
Your assertion of 5 cu ft for sealed and 10 cu ft for PRs, being a requirement for ideal case may not be all that big of a concern. Give this some thought. Build a 7.5 cu ft box (mid line), have caps that would close the PR holes and measure. Imagine what a great contribution this would be...


----------



## Ilkka

Hi guys,

I will be out of town for the rest of the week. The results are progressing but there's still a lot of work to do.

And if someone's been following the thread over at the other forum. Here's a clarification.



Craig Chase said:


> I have held out several olive branches to Ilkka in regards to all sorts of stuff. He did finally reciprocate a few months ago.


Sure thing. :sarcastic: Around a year ago he made a "suggestion" to me that included all sorts of "interesting" stuff. I didn't reciprocate then and I won't reciprocate in the future. Our goals and means are just too different. End of story.

It has also been said that I don't have the resources to do proper listening tests. Now where did that come from? :dontknow: I have a small but acoustically really good listening room, both Velodyne SMS-1 and Behringer DCX2496 & Room EQ Wizard (which I prefer) for EQ'ing purposes. I can switch subwoofers in a couple of seconds. Add comfy listening chair and loads of good music and movies. Believe me, I have been listening all the subs I've had or have at the moment, probably more than many think. I will post my comments but IMO they are not as useful as objective measurements. When personal preferences and room acoustics (plus EQ) come into play, things get more difficult. 2m GP is an environment that favours all subs equally.


----------



## ssabripo

Ilkka said:


> Sherv! Good to see you here.
> 
> Yeah, it would be fun to see how your sono would fare. But I don't think we have to start a shipping trust fund. I know there is at least one or two LARGE sonosubs in the builds here in Finland as we speak. Next measurement session should be even more interesting. :rubeyes:


no worries Ilkka....I've missed you over there, measurements and all, but is good to see you doing what you do best, specially with the new CEDIA requirements in the mix. You are setting a very good baseline....keep up the good work. I'll be following this thread.

ps- any more info on the big sonotubes being built? what drivers? what volume and Fb?



steve nn said:


> Oops!.. I forgot:duh: Well it was all your yak about the 54 that got me going, so buck up my friend.:boxer: OK.. but Think of all the money your $aving by living through Ilkka, she's got to like that? ha ha


yeah....that would be a great idea, except, I would be miserable without my two little boys:sad: 
Plus, I'm too much of a sissy for the cold weather....I turn gay real quick in the cold :bigsmile: 


ps- I apologize to all those who have PM'd me asking to come and participate more...I am extremely busy trying to open up my wife's business, that I dont even have time to watch TV or anything. I hope to get back to this hobby soon enough

pss- looks like they shutdown the other thread over there again....surprise surprise:snoring:


----------



## mojomike

Ilkka said:


> Hi guys,
> 
> I will be out of town for the rest of the week.


Whaaaaat? You mean you actually have a life outside the world of subwoofers? That's not right! :no:


----------



## SteveCallas

Subjective subwoofer shootouts make it easier for some people to hype the "sub of the month". Objective measurements conducted at a later date typically show that sub to be a poor performer, so the cycle begins anew. It's gotten pretty sad.


----------



## Blaser

Which subwoofer(s) are you talking about?:innocent:


----------



## Blaser

Ilkka said:


> Hi guys,
> 
> I will be out of town for the rest of the week. The results are progressing but there's still a lot of work to do.
> 
> And if someone's been following the thread over at the other forum. Here's a clarification.
> 
> 
> Sure thing. :sarcastic: Around a year ago he made a "suggestion" to me that included all sorts of "interesting" stuff. I didn't reciprocate then and I won't reciprocate in the future. Our goals and means are just too different. End of story.
> 
> It has also been said that I don't have the resources to do proper listening tests. Now where did that come from? :dontknow: I have a small but acoustically really good listening room, both Velodyne SMS-1 and Behringer DCX2496 & Room EQ Wizard (which I prefer) for EQ'ing purposes. I can switch subwoofers in a couple of seconds. Add comfy listening chair and loads of good music and movies. Believe me, I have been listening all the subs I've had or have at the moment, probably more than many think. I will post my comments but IMO they are not as useful as objective measurements. When personal preferences and room acoustics (plus EQ) come into play, things get more difficult. 2m GP is an environment that favours all subs equally.


I don't know how and why some some are claiming that measurements alone can not determine Sound quality I wonder what it is that could be determined by ear (whose ear are we talking about:R )and not by measurments ...


----------



## jmcomp124

blaser said:


> I don't know how and why some some are claiming that measurements alone can not determine Sound quality I wonder what it is that could be determined by ear (whose ear are we talking about:R )and not by measurments ...


Disclaimer before I say what I am going to say: 
I am not a proponent of subjective listening of a certain individuals test methodology but a strong supporter of Ilkka's measurement methodology and what it offers. 

But this is my belief. No matter how sophisticated or good a measurmenet methodology or instruments are, there is absolutely no substitute for your ear being the final judge. 

It is simply not feasible to capture everything your ear can do, with just measurements and give a final word on Sound Quality. Think of the complexity of the design of ear ossicles and how they are wired to your brain and the billions of neurons that interpret and translate those signals and which is where psycho-acoustics come into play. 

I look at these measurements as valuable data that are guidlelines. But at the end of the day my ear and my brain judge how good the sound quality is or is not.

A lot of people will disagree with me on this subject and there are a lot who will agree. 
Im my mind, we need both. Measurements and "Unbiased" subjective listening tests. It is music to my ears that Ilkka is considering doing some detailed listening tests that he can publish. I thought he didn't have those resources (room, enough interested qualified people that would include musicians) but apparently he has and that is wonderful. I will look forward for those opinons too!


----------



## Kevin_Wadsworth

Wow! Ilkka managed to get a thread closed without posting to it or even being member of the forum. Impressive.


----------



## WillyD

> But this is my belief. No matter how sophisticated or good a measurmenet methodology or instruments are, there is absolutely no substitute for your ear being the final judge.


And it is my belief that since we are each different, and since the brain is involved with hearing, the only way to objectively, equally, and accurately compare subwoofers is Ilkkas method.

I brought up the 'how objective measurements determine SQ' and vice versa on more than one occasion in a few of the 'shootout' threads. I am sure you know what I am referring to. No one cared, not even the person doing these shootouts. He didn't care about the relation between the objective data and the subjective listening tests in the least.

All I know is, if I had to choose between someone providing these subjective listening tests or Ilkka's method of testing, I'd without a doubt choose Ilkka's. His can tell me _much more_ about a subs overall performance than some flowery **** about how deep, tight, or loud a sub sounds. 

But hey, thats just my opinion.


----------



## Mark Seaton

When it comes to measurement and the listening experience, one doesn't have a lot of merit without acknowledgement of the other.

While we talk about now having a much better understanding of what contributes to the subjective listening experience and what doesn't, it's important to remember that things like the CEA limits and other metrics we value all evolved from observations made in listening and measurement followed by a lot of testing. What matters most is the correlation of measurements to observations and experiences.


----------



## Guest

Have to agree with Mark here: use and correlate both objective data and subjective listening. Benn following both sub threads for quite some time. Love the data that Ilkka is putting up; it is critically important, but perhaps not the be-all and end-all, in my opinion. It is great piece of work and effort well-spent. A good place to start your auditions, and to perhaps save time not listening to subs that do not test well.

Best example I have experienced was a Stereophile test CD that demonstrated the principle that accurate measurements do not equate directly with the sound that a listener might prefer. It played back a track that was recorded with three or four different microphones, and all tested ruler flat. Strangely, each one had a unique and different sound, and you pick each microphone out as sounding quite different from the others, although each measured flat. Great demo. Let me know if anyone wants info on CD, track, etc. 

I still look forward to further tests every day!

Tom


----------



## SteveCallas

Mark said:


> What matters most is the correlation of measurements to observations and experiences.


Right, but that's still going to be a personal preference matter. Some will like a sound and see that the sub has high 3rd order distortion - someone else will dislike the sound and see that the sub has high 3rd order distortion. What do we make of that? Only each individual can extract something useful from it. 

I think the reality is that subwoofer sound quality is so highly reliant upon what's actually going on in the 80-500hz range that to truly do a subjective sub shootout, there should be no speakers in the mix. Just the subs crossed over at 80hz, level matched, tested unsighted. That would cause a few people to rethink what they thought they knew :daydream:.....burst a few bubbles if you will. Things like transient response in the infrasonics aren't worth worrying about - give yourself plenty of low distortion headroom with deep and linear extension in room and you are good to go. I think the LLT tested by Ilkka will show that it is definitely good to go :R 

Subjective shootouts are much better put to use when comparing full range speakers in my opinion, and even then, I really don't trust too many impressions other than my own.


----------



## Manic Miner

Your ears (and in the case of subwoofers, also your chest, stomach and buttocks) should always have the last say. BUT, it should be YOUR ears, and not someones elses


----------



## Vader

I would agree in general that how good a sub sounds is paramount, but not in this case where a clear bias is being shown on that other site, towards "the flavor of the month", as it were. Ilkka's testing levels the ground between subs, bursting quite a few bubbles over there ("...120dB at the listening position... All the best."). They regularly censor or delete posts, or even entire threads, that go against said bias, and this invalidates any subjective conclusions. It's even worse when the bias is obviously slanted towards paying advertisers on the site. Given the choice between qualitative observations and quantitative data, I will take quantitative any day. 

On yet another site, they are not even consistant with the data they take. For example, one sub has a given set of measurements (THD, Impulse, etc) that look quite good (AFAIU), but there is an entire thread stating that, _based on the measurements_, the sub is bantha fodder (the site as a whole shows a strong bias against this manufacturer). In the discussion of a favored sub however, which fares much worse in the testing, it is concluded that it is a "strong performer", again, based solely on the data.

I am so thankful for Ilkka, and HTS!


----------



## WillyD

> When it comes to measurement and the listening experience, one doesn't have a lot of merit without acknowledgment of the other.


The measurement alone is much more valuable than another's listening experience on its own, IMO.


----------



## Vader

> The measurement alone is much more valuable than another's listening experience on its own, IMO.


I concur.


----------



## Blaser

jmcomp124 said:


> But this is my belief. No matter how sophisticated or good a measurmenet methodology or instruments are, there is absolutely no substitute for your ear being the final judge.


Relatively (my ear is the final judge for me only... not for you), not absolutely. 


> It is simply not feasible to capture everything your ear can do, with just measurements and give a final word on Sound Quality


Why? *do you have any example?* How do you calibrate your ear?:scratch: What is SQ to you may be Bad SQ for others....This is subjective. There is nothing a "perfectly calibrated ear", and a "perfect flat and unbiased brain":R would tell you that the measurements could not....unless some measurements are missing.


> I look at these measurements as valuable data that are guidlelines. But at the end of the day my ear and my brain judge how good the sound quality is or is not.


Again: for you only, pobably not for me (in blind listening tests some will find a sub has better sound quality, while others will find the other one to be betteronder: .... What is the final judge?:R ) 
Another case is some do like for ex. a peak at 35 Hz, and it sounds very good to their ears, while other do not....


> A lot of people will disagree with me on this subject and there are a lot who will agree.
> Im my mind, we need both. Measurements and "Unbiased" subjective listening tests. It is music to my ears that Ilkka is considering doing some detailed listening tests that he can publish. I thought he didn't have those resources (room, enough interested qualified people that would include musicians) but apparently he has and that is wonderful. I will look forward for those opinons too!


Well, the listening tests are maybe a plus (again to confirm the measuements) but not a must....Tell me frankly: do you know any good looking measured sub on paper that sounds bad:cunning: 

If ever Ilkka published his listening tests, I even expect him to say something like: " Sub A was more accurate than sub B to my ear....and *this is expected as showed by the measurments* of group delay, dynamic output compression...." Do you get my point?


----------



## JimP

Tallen01 said:


> Best example I have experienced was a Stereophile test CD that demonstrated the principle that accurate measurements do not equate directly with the sound that a listener might prefer. It played back a track that was recorded with three or four different microphones, and all tested ruler flat. Strangely, each one had a unique and different sound, and you pick each microphone out as sounding quite different from the others, although each measured flat. Great demo. Let me know if anyone wants info on CD, track, etc.
> 
> I still look forward to further tests every day!
> 
> Tom


That's why previous test methods don't quantify what the ear hears.

Even if we reach the point where testing methods more precisely reflect what the ear hears, there is still the personal preference element.


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## Vader

> there is still the personal preference element


Personally, I do not like Bose systems, because they color the sound much more than other systems, and this is reflected in the FR graphs of the satellites and so-called "bass module" (ie. the bass hole, low dynamic range, etc). However, I have a friend that absolutely swears by Bose sound. So, although Bose sounds good to _his ear_, it is not accurate to the source material. Thus, his preference is just that, personal preference, and is not useful in making subjective comparisons...


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## Chrisbee

I trust Ilkka's graphs more than any personal subjective opinions.
My wife still prefers her big SVS cylinder to my IB.
She is deaf to my protestations! :coocoo: 

People should always ask for the speakers to be muted during a sub demo. IMO.
This way, you can really hear the junk being pumped out by the sub in question!
Coloration, rattles, buzzes, honks and everything else are all cruelly exposed.
You don't think some subs are horribly colored? Try muting your speakers. :nerd:


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## Blaser

Vader,

I agree with you!


----------



## jmcomp124

blaser said:


> Relatively (my ear is the final judge for me only... not for you), not absolutely.
> 
> Why? *do you have any example?* How do you calibrate your ear?:scratch: What is SQ to you may be Bad SQ for others....This is subjective. There is nothing a "perfectly calibrated ear", and a "perfect flat and unbiased brain":R would tell you that the measurements could not....unless some measurements are missing.
> 
> Again: for you only, pobably not for me (in blind listening tests some will find a sub has better sound quality, while others will find the other one to be betteronder: .... What is the final judge?:R )
> Another case is some do like for ex. a peak at 35 Hz, and it sounds very good to their ears, while other do not....
> 
> 
> Well, the listening tests are maybe a plus (again to confirm the measuements) but not a must....Tell me frankly: do you know any good looking measured sub on paper that sounds bad:cunning:
> 
> If ever Ilkka published his listening tests, I even expect him to say something like: " Sub A was more accurate than sub B to my ear....and *this is expected as showed by the measurments* of group delay, dynamic output compression...." Do you get my point?


Yeah, I get your point :bigsmile:

I don't know of any good looking measured sub on paper that sounds bad, but I know of a few that look bad measured but sounds good :heehee: I mean the ones with the "hump" in the FR that so many make a big deal about. Do you listen to tubes? How do they measure on paper?


----------



## Mark Seaton

WillyD said:


> The measurement alone is much more valuable than another's listening experience on its own, IMO.


I agree with you Willy, and while some added observations alongside the measurements give much more value, you missed the point I intended to make.

My point is that we take for granted what a beneficial set of measurements are. The new CEA measurements would never have been devised if someone didn't listen and try to better correlate what was heard vs. what was measured.

How do we know the relative importance of smooth or flat response vs. higher maximum output? How do we know that phase response or time smearing isn't a much more dominant quantity than low distortion at high output or even frequency response?

Someone who was measuring also listened to the devices they were measuring.


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## WillyD

> you missed the point I intended to make.


I assure you I didn't miss the point, for it was quite clear.


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## jmcomp124

.(Is there an option to delete a post when one thinks it is not necessary for the post at a later time?).
I couldn't find an easy delete link.


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## SteveCallas

Mark said:


> My point is that we take for granted what a beneficial set of measurements are. The new CEA measurements would never have been devised if someone didn't listen and try to better correlate what was heard vs. what was measured.
> 
> How do we know the relative importance of smooth or flat response vs. higher maximum output? How do we know that phase response or time smearing isn't a much more dominant quantity than low distortion at high output or even frequency response?
> 
> Someone who was measuring also listened to the devices they were measuring


So you're saying we need CEDIA to tell us what sounds good? Subjective sound quality varies from person to person, so results from measurements will be interpretted in regards to sound quality differently from person to person as well.


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## brucek

jmcomp124 said:


> .(Is there an option to delete a post when one thinks it is not necessary for the post at a later time?).
> I couldn't find an easy delete link.


Just delete all the text and generally a moderator or admin will delete it....


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## Chrisbee

SteveCallas said:


> So you're saying we need CEDIA to tell us what sounds good? Subjective sound quality varies from person to person, so results from measurements will be interpretted in regards to sound quality differently from person to person as well.


After more than 40 years trying to get quality bass I now trust Ilkka's figures more than my own ears. Ears can learn. (or be taught) 

I made the progression from my two large DIY bandpass boxes (professionally designed 6th order series) to an SVS cylinder. Then after a couple of years more to an IB. This has taught me that what I thought was wonderful can be totally eclipsed by something better. Each of my subs easily extended well below 20Hz at high SPLs. (100+dB(C)) Each new sub produced much lower audible coloration and distortion than the last. Each sub sounded perfect to my ears until the next one came along. 

It is difficult to imagine an improvement on what I have now. I can now clearly hear the weaknesses in my past subwoofers. (I still have them) This is not a matter of taste. It is an educated ear simply from listening to high quality bass from a very high quality subwoofer over a length of time. Subjective testing (or subjective opinion) is only as good as the best subwoofer you have ever lived with. (not just heard at a brief demo) Subjective audio memory is almost worthless as a measurement tool.


----------



## SteveCallas

Chris said:


> Subjective testing (or subjective opinion) is only as good as the best subwoofer you have ever lived with. (not just heard at a brief demo) Subjective audio memory is almost worthless as a measurement tool.


Absolutely.



Chris said:


> It is difficult to imagine an improvement on what I have now












I'll be nice :innocent:


----------



## Mark Seaton

SteveCallas said:


> So you're saying we need CEDIA to tell us what sounds good? Subjective sound quality varies from person to person, so results from measurements will be interpretted in regards to sound quality differently from person to person as well.


I think you have your organizations confused. CEDIA (Custom Electronics Design & Installation Association) has nothing to do with the testing Ilkka and others have been doing. CEA (Consumer Electronics Association) on the other hand has pulled together working groups to develop various standards and quantifications. The CEA didn't decide what sounds good, rather many experts who have done years of research on the topic conferred to collaborate what is more or less audibly offensive or identifiable. There is no indication of what subwoofer will be preferred in listening, as application and use are still to be determined for each user's situation.


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## Chrisbee

Steve 

My latest curve is tilted up to 12Hz.
We may be drifting from the plot.


----------



## SteveCallas

Mark said:


> I think you have your organizations confused


:duh:



> rather many experts who have done years of research on the topic conferred to collaborate what is more or less audibly offensive or identifiable


Is there anywhere one can go to read about the established standards and the studies behind them?


----------



## Ilkka

Tallen01 said:


> Best example I have experienced was a Stereophile test CD that demonstrated the principle that accurate measurements do not equate directly with the sound that a listener might prefer. It played back a track that was recorded with three or four different microphones, and all tested ruler flat. Strangely, each one had a unique and different sound, and you pick each microphone out as sounding quite different from the others, although each measured flat. Great demo. Let me know if anyone wants info on CD, track, etc.
> 
> I still look forward to further tests every day!
> 
> Tom


I don't quite agree with the example. Different sounding full range mics having different polar patterns (and measured indoors) do not quite relate to subwoofer measurements.


----------



## Ilkka

SteveCallas said:


> Is there anywhere one can go to read about the established standards and the studies behind them?


Here's some info.

http://www.almainternational.org/2006_symposium_papers/2005-12-20-CEA-2010-DRAFT.pdf

http://www.gedlee.com/downloads/THD_.pdf

http://www.gedlee.com/downloads/distortion_perception.ppt


----------



## SteveCallas

Thanks.


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## Ilkka

Interesting opinions regarding the subjective vs. objective evaluation of subwoofers. I naturally agree that people should make the final decision with their ears, in their own room, but unfortunately very often that's not possible. And even then one might not get the right picture if the subwoofer(s) wasn't/weren't properly set up. Velodyne was the first one to really understand the power of equalization with their greatly successful DD-series. Since then powerful external devices such as Behringer Feedback Destroyer, Velodyne SMS-1, and Onix R-DES have rolled on the market. Sadly owning such a device doesn't ensure that one knows how to efficiently use one. But when used properly, EQ can have a huge impact on subwoofer's performance, especially on the 'sound quality' part. This is the part where most amateur and also professional subwoofer reviews and comparisons fail. Most of the problems in or lack of 'sound quality' are caused by wrong or no use of EQ. 

IMO subwoofers are fairly simple devices. Having almost omni-directional radiation pattern, producing only a small part of typical music signal (90% of the music don't have much content below ~40 Hz), and because human hearing is relatively insensitive/inaccurate for low frequencies. All the things which DO NOT apply when talking about full range speakers. With subwoofers, the (in-room) frequency response is easily the most effective and therefore the most important variable of subwoofer's performance. Close behind come the maximum output capability and harmonic distortion (usually very heavily related). All other variables such as group delay, spectral decay etc. can be derived from these variables.

I don't often use the term 'sound quality'. That's because IMO there's no absolute sound quality. Instead there are different tastes and flavors. It can not be said that all people like the certain sounding subwoofers. Or that some certain subwoofer is absolutely rubbish because some people don't like it. The XTZ 99 W12 subwoofer that I recently tested is a perfect example of this. It measures relatively bad for a conventional subwoofer: not much output below 50 Hz but very high output capability and low distortion in 50-100 Hz range. And still it's the biggest selling subwoofer in the whole Scandinavia. Not all people value the same qualities; some like a bass that thumps and kicks like a mule, probably because they are used to car audio subwoofers which are usually set at least 20-30 dB above the rest of the system. Some like more refined and subtle bass which doesn't draw much attention to itself. Who am I to say which one is more 'right' when both enjoy their subwoofers. Of course certain acoustical instruments should sound like their real life counterparts, but it isn't that simple. Different music styles require different kind of frequency response/equalization. While an upright bass may sound the best with a relatively flat frequency response, 80's/90's rock or modern heavy metal sounds much better with a slightly boosted 50-70 Hz range. I could give numerous examples but I think you'll get the picture.

I will probably put more weight on the objective data than most people. That's because I have measured and listened to so many subwoofers, and I haven't yet encountered a subwoofer (with a possible exception in the form of Axiom Audio EP-600 which strange behaviour was probably caused by faulty electronics/driver) which subjective performance could not be explained with its objective measurements or vice versa. Now usually at this point some wise guy points out that one can not measure 'sound quality'. That's of course correct but not in the way he/she probably meant. As I said earlier, there is no absolute 'sound quality' - this magical term means different things to different people. That also means that different people value different kind of objective data. Therefore it can not be said which subwoofer is preferred by most people. Measurements can show which subwoofer produces the original signal with as little colouration as possible, but I'm 100% certain that this subwoofer isn't preferred by all people. Same thing with subjective evaluation - if one person prefers certain subwoofer, how can you know your preference will be identical or even similar to his?


----------



## Geoff Gunnell

Bravo! Excellent, Ilkka!


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## Chrisbee

Indeed.

It is interesting how coloration is now an accepted factor in subwoofer performance.

Logic suggests that the powerband frequencies involved are all too low (and thus wavelengths far too long) to be affected by enclosure dimensions or design.

Yet subwoofer coloration can be very obvious.


----------



## Mark Seaton

Ilkka said:


> Here's some info.
> 
> http://www.almainternational.org/2006_symposium_papers/2005-12-20-CEA-2010-DRAFT.pdf
> 
> http://www.gedlee.com/downloads/THD_.pdf
> 
> http://www.gedlee.com/downloads/distortion_perception.ppt


Hi Ilkka,

Good to see you back from some time away from this madhouse. 

For anyone just scanning, the middle "THD_.pdf" link is a great read as it gives some greater historical perspective and precedence to the work Earl Geddes & Lidia Lee have done and how all of it has influenced things like the newer CEA measurement standard.


----------



## Mark Seaton

Ilkka said:


> IMO subwoofers are fairly simple devices. Having almost omni-directional radiation pattern, producing only a small part of typical music signal (90% of the music don't have much content below ~40 Hz), and because human hearing is relatively insensitive/inaccurate for low frequencies. All the things which DO NOT apply when talking about full range speakers. With subwoofers, the (in-room) frequency response is easily the most effective and therefore the most important variable of subwoofer's performance. Close behind come the maximum output capability and harmonic distortion (usually very heavily related). All other variables such as group delay, spectral decay etc. can be derived from these variables.
> 
> I don't often use the term 'sound quality'. That's because IMO there's no absolute sound quality. Instead there are different tastes and flavors. It can not be said that all people like the certain sounding subwoofers. Or that some certain subwoofer is absolutely rubbish because some people don't like it. The XTZ 99 W12 subwoofer that I recently tested is a perfect example of this. It measures relatively bad for a conventional subwoofer: not much output below 50 Hz but very high output capability and low distortion in 50-100 Hz range. And still it's the biggest selling subwoofer in the whole Scandinavia. Not all people value the same qualities; some like a bass that thumps and kicks like a mule, probably because they are used to car audio subwoofers which are usually set at least 20-30 dB above the rest of the system. Some like more refined and subtle bass which doesn't draw much attention to itself. Who am I to say which one is more 'right' when both enjoy their subwoofers. Of course certain acoustical instruments should sound like their real life counterparts, but it isn't that simple. Different music styles require different kind of frequency response/equalization. While an upright bass may sound the best with a relatively flat frequency response, 80's/90's rock or modern heavy metal sounds much better with a slightly boosted 50-70 Hz range. I could give numerous examples but I think you'll get the picture.
> 
> I will probably put more weight on the objective data than most people. That's because I have measured and listened to so many subwoofers, and I haven't yet encountered a subwoofer (with a possible exception in the form of Axiom Audio EP-600 which strange behaviour was probably caused by faulty electronics/driver) which subjective performance could not be explained with its objective measurements or vice versa. Now usually at this point some wise guy points out that one can not measure 'sound quality'. That's of course correct but not in the way he/she probably meant. As I said earlier, there is no absolute 'sound quality' - this magical term means different things to different people. That also means that different people value different kind of objective data. Therefore it can not be said which subwoofer is preferred by most people. Measurements can show which subwoofer produces the original signal with as little colouration as possible, but I'm 100% certain that this subwoofer isn't preferred by all people. Same thing with subjective evaluation - if one person prefers certain subwoofer, how can you know your preference will be identical or even similar to his?



Great post Ilkka,

Not surprisingly, I generally agree with your above observations.

While describing personal preferences in terms of "sound quality" is not a clear thing, it is not quite as fuzzy as some make it out to be. I would suggest that you can sum up your above descriptions as to what can be determined from measurements as "sound or sonic character."

I also agree that subwoofers are relatively simple systems. The complexities really only come into play in the non-linearities. As simple as subwoofers are in basic operation, all subwoofers have reproduction errors, and of course the room contributes the largest error.

I do think preferences can be largely predicted if we have some baseline from which to guage a listener's preferences prior to listening such as having a description of the perceived differences between a few different and known examples. In my experience listeners aren't so much "hearing" different things as they are differently prioritizing qualities and offenses. If we go back and look at what speakers are subjectively deemed better for one sort of playback over another, usually the strengths and weaknesses follow what is more or less likely to be identified with the characteristics of the program material. 

A great example is inteligibility of movie dialog vs. music playback. Early religous hymms largely originated from the need to overcome the poor inteligibility in houses of worship where stone and other reflective construction made spoken word rather hard to follow. The rate of change or modulation of sound in music vocals will be much slower than is required for common speech inteligibility. It should not come as any surprise that different acoustic spaces and loudspeakers would show fewer offenses in one use over the other.

Full range speakers are much more complex in the correlation of measured quantities to sonic character, but we continue to improve in this regard, although the best work in this arena is discussed much more in the pro audio world than in the consumer world, as the marketers know that confusion leads to people not purchasing. From my experiences, the pro audio practitioners have a much better understanding of how to get a desired result, and many of the stereotypes of bad sound come less so from a lack of capability, but more from lower expectations and aspirations.


----------



## Ilkka

Okay, here's some more info about the drama I mentioned before.

This is what happened to the other TC-2000 15" I have in my sealed sonosub.










This time I used the Behringer DCX2496 to make the frequency response flatter (L/T if you prefer). This is the frequency response I was able to measure. -6 dB point is at ~16 Hz.










I'm not 100% certain at which point the part of the upper surround came off. There is a small possibility that it was already damaged during the first round of testing, therefore affecting the measured results, especially the CEA 2010 values.

In any case, we had to abort these second measurements during the compression sweeps.

I contacted TC-Sounds and they were naturally very sorry of what happened. They offered to send me a new top assembly ASAP, but since the damage was relative small, I wanted to see if it was fixable. I purchased special Loctite 406 glue + 770 primer for the purpose and glued down the part of the surround. After 24 hour cure time I will be able to see if it holds. If not, TC-Sounds will send me a new top assembly. I would like to thank them for handling this issue very professionally. :clap:


----------



## Ilkka

I just tested if the glue holds - it holds. :T

It's nothing short of amazing and partly sad how much power these drivers can take/require. I can clip my 2000W amp with a single TC-2000 in free air without bottoming the driver. I can't measure the excursion accurately, but it looks like it barely touches the 28mm Xmax. I wish they were a bit more sensitive...


----------



## cjwhitehouse

Mark Seaton said:


> Hi Ilkka,
> 
> Good to see you back from some time away from this madhouse.
> 
> For anyone just scanning, the middle "THD_.pdf" link is a great read as it gives some greater historical perspective and precedence to the work Earl Geddes & Lidia Lee have done and how all of it has influenced things like the newer CEA measurement standard.


If anyone is tempted to try and replicate Keith Howard's work, be aware that computing the Gedlee Metric is a bit of a minefield. As Keith points out in a later article he wrote for Stereophile, normalizing the polynomial coefficients correctly is key to getting the right answer. However, having corresponded with Keith about this, even his correction mentioned in the Stereophile article does not fully correct the values presented in this earlier article. This is probably not the right thread to fully discuss this, but be aware that this is very much still a work in progress. :reading:


----------



## WillyD

> I contacted TC-Sounds and they were naturally very sorry of what happened. They offered to send me a new top assembly ASAP, but since the damage was relative small, I wanted to see if it was fixable. I purchased special Loctite 406 glue + 770 primer for the purpose and glued down the part of the surround. After 24 hour cure time I will be able to see if it holds. If not, TC-Sounds will send me a new top assembly. I would like to thank them for handling this issue very professionally.


I knew they'd treat you right, but still, no excuse. Did they happen to tell you if they've had any other reports of this happening with their subs in the past year? I am just curious.


----------



## Ilkka

WillyD said:


> I knew they'd treat you right, but still, no excuse. Did they happen to tell you if they've had any other reports of this happening with their subs in the past year? I am just curious.


No, they didn't tell...though I didn't ask. I would think this is pretty unusual.




> I wonder if Ilkka will be able to get his hands on a F113....


As soon as the 230V versions are done, I will test one. Hopefully already this fall.


----------



## Manic Miner

There is already a 230V version on its way to Norway. In fact the guy who ordered it got it last week, but JL had by mistake sent him a 110V version so it went up in smoke


----------



## Ilkka

Manic Miner said:


> There is already a 230V version on its way to Norway. In fact the guy who ordered it got it last week, but JL had by mistake sent him a 110V version so it went up in smoke


Oh, that is good news. Not the "went up in smoke" part though. :R


----------



## Manic Miner

Yes it will be great fun to see how it stacks up against the new Ultra with the Ultra in sealed mode. I don't know for sure, but maybe that data can be used to predict how an SB13-Ultra will perform compared to the JL?


----------



## mojomike

Manic Miner said:


> Yes it will be great fun to see how it stacks up against the new Ultra with the Ultra in sealed mode. I don't know for sure, but maybe that data can be used to predict how an SB13-Ultra will perform compared to the JL?


I somehow doubt that running the new Ultra in sealed mode would show that sub to it's best advantage. It is first and foremost a big ported sub and I'll bet with all ports open or one port plugged, the Ultra will shine brightest. 

Now, a purposely designed SB13-Ultra, that should be very interesting.


----------



## Ilkka

Manic Miner said:


> Yes it will be great fun to see how it stacks up against the new Ultra with the Ultra in sealed mode. I don't know for sure, but maybe that data can be used to predict how an SB13-Ultra will perform compared to the JL?


I haven't even seen a formal announcement for an SB13-Ultra?

If it's coming, I would bet it will be much smaller and has more powerful amp than the PB13-Ultra. Therefore predicting its performance will be pretty inaccurate.


----------



## Ed Mullen

Ilkka said:


> I haven't even seen a formal announcement for an SB13-Ultra?
> 
> If it's coming, I would bet it will be much smaller and has more powerful amp than the PB13-Ultra. Therefore predicting its performance will be pretty inaccurate.


Correct. If we ever release an SB13-Ultra (which would use a much smaller cabinet), it likely won't use the existing underhung motor topology. 

The existing underhung woofer has been optimized to function well in the large cabinet in a (primarily) reflex alignment. With that said, the FR in sealed mode is excellent for small to mid-size rooms with a wide F6 bandwidth and a 2nd order roll-off (taking good advantage of available room gain), and the underhung motor tolerates a sealed alignment well in this size cabinet.

So I agree with Ilkka, don't use the performance of the PB13-Ultra in reflex or sealed mode to gauge/estimate the performance of an SB13-Ultra (if we ever release said model) - they will be two different animals.


----------



## Manic Miner

It was just pure speculation on my behalf. I thought that the new Ultra driver was made for use in both an SB and a PB just like the 12.3.

It will be interesting to see how both the JL and the Ultra performs respectively, even though the only thing they have in common is that they are both subwoofers


----------



## Ed Mullen

Manic Miner said:


> It was just pure speculation on my behalf. I thought that the new Ultra driver was made for use in both an SB and a PB just like the 12.3.
> 
> It will be interesting to see how both the JL and the Ultra performs respectively, even though the only thing they have in common is that they are both subwoofers



A better way to describe it would be the Ultra woofer was designed to function well _in this size box_ in both reflex and sealed alignments. If we built a much smaller SB13-Ultra, it would use a motor topology optimized for that size box.


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## WillyD

> As soon as the 230V versions are done, I will test one. Hopefully already this fall.


Good to hear. :nerd:


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## Ilkka

http://www.hometheatershack.com/forums/subwoofer-tests/4652-lms-5400-rl-p18-buy.html

Please check the new info regarding the LMS-5400 / RL-p 18" buy-in thread.


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## adogand6kids

This is my first time following a sub testing cycle. I know there must be a large amount of data processing and preparation for posting the results. I was just wondering if Ilkka could give us a rough estimate on when we might expect to see the full data sets on the tested subs (especially the DIY Rhythmik). I am not trying to rush, I just have no idea what the expected time frame is. Do you post all the results at the same time, or do you post each sub's results as they become available? Thanks in advance for the info.


----------



## Ilkka

adogand6kids said:


> This is my first time following a sub testing cycle. I know there must be a large amount of data processing and preparation for posting the results. I was just wondering if Ilkka could give us a rough estimate on when we might expect to see the full data sets on the tested subs (especially the DIY Rhythmik). I am not trying to rush, I just have no idea what the expected time frame is. Do you post all the results at the same time, or do you post each sub's results as they become available? Thanks in advance for the info.


There's still a lot of work to do. Rough estimate would be somewhere around 3-4 weeks (though don't kill me if it takes longer).

I will post all the results at the same time.


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## adogand6kids

_Rough estimate would be somewhere around 3-4 weeks (though don't kill me if it takes longer)._

Thanks for the reply. No death threats intended in the question, I just didn't have any idea when to expect the results.


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## Ilkka

*Lms-5400!*

Very good news regarding the LMS-5400 buy-in. Please see the link below.

http://www.hometheatershack.com/forums/subwoofer-tests/4652-lms-5400-rl-p18-buy-2.html#post39918


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## Geoff Gunnell

Thought I'd copy this forward a few pages for convenience (orig. posted 5/13/07):



Ilkka said:


> I won't share it yet but here's the updated spreadsheet. The 20-39PC+ had the newest 12.3 driver and its results will be comparable to the PB12-Plus.
> 
> Added:
> HSU VTF-3 MK3 ME
> SVS 20-39PC+ 12 Hz
> SVS 20-39PC+ 16 Hz
> SVS 20-39PC+ 20 Hz
> XTZ 99 W12 MO
> XTZ 99 W12 ME
> 
> MO = maximum output/2 ports open
> ME = maximum extension/1 port open


----------



## SteveCallas

It's been nealy two months Ilkka, how much longer are you going to keep us in suspense? :dontknow:


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## Ilkka

SteveCallas said:


> It's been nealy two months Ilkka, how much longer are you going to keep us in suspense? :dontknow:


Hi Steve,

I can imagine that these last ~7 weeks have felt like a really long time for you rest, but to me it has felt like 7 days or so. :coocoo: I don't want to get into details but I've been really busy with both personal and business stuff. I for example got a new job which has took some time from making the results ready for you. It is also a holiday season here in Finland which slows down things a bit. And if you are thinking about some amount of work needed to transform these measurements into "readable" form, multiply it at least by 10, and you're barely there. :dizzy: 

So...the results are definitely on their way, I just can't give you an exact date yet.

Back to doing stuff that pays bills...


----------



## Ilkka

Okay, UPDATE!

It won't take long now...less than a week.  :jump:


----------



## crackyflipside

Ilkka said:


> Okay, UPDATE!
> 
> It won't take long now...less than a week.  :jump:


:jump:

Ilkka, where would we be without you? :daydream:


----------



## no. 5

crackyflipside said:


> :jump:
> 
> Ilkka, where would we be without you? :daydream:


Conceivably, we would have to figure out how to measure these things for ourselves. :mooooh:


----------



## Geoff Gunnell

Our nearest shopping mall manager would be saying to us "You want to come into our parking lot at night, plug into our power, and do WHAT?"


----------



## crackyflipside

So Ilkka are you going to post all the results at once or is this going to be a few at a time?

I can't wait for the results! :banana:


----------



## Ilkka

I will start posting the results soon.  Unfortunately the English language comments are not ready yet (I've posted the Finnish comments on DVDPlaza). I will update them as soon as possible. I HAVE added my comments (English) for subwoofers tested last spring.


----------



## Ilkka

*The results are posted!*


----------



## Mark Seaton

Ilkka said:


> *The results are posted!*


Hi Ilkka,

I'd like to be the first to post a big :T for all of your efforts here and the very interesting data.

Hopefully in the next session I'll have some subwoofers to contribute, but I have to say I felt a lot better seeing this dose of reality in what products out there *really* do.  There are some great performers in the group, but they are all "human" and still abide by known physics.

Great job. :clap:


----------



## Ilkka

Mark Seaton said:


> Hi Ilkka,
> 
> I'd like to be the first to post a big :T for all of your efforts here and the very interesting data.
> 
> Hopefully in the next session I'll have some subwoofers to contribute, but I have to say I felt a lot better seeing this dose of reality in what products out there *really* do.  There are some great performers in the group, but they are all "human" and still abide by known physics.
> 
> Great job. :clap:


Hi Mark, and thank you! :hail: I would be honoured to measure some of your creations. Though I'm 100 % sure even they won't defy physics, but still. :sarcastic:


----------



## Ilkka

I checked the "other" forum, and noticed that "thylantyr" had some concerns about power issues. 

We used 2 dedicated 230 V / 16 A lines. So when we used two amplifiers, each of them had its own line. Extension cord length was ~40 meters. Voltage sag was extremely small. 16 A circuit breakers (per line) didn't break at once.

The t-amp TA2400 MK-X is pretty affordable, but quite powerful amp. You might want to check out these measurements. The text part says that when he tested it at 4 ohm bridged load, his house's circuit breaker tripped, but before that he saw around 2200 Watts. Surely some of the subwoofers could have used more power (especially when it comes to burst tests), but when you look at the power compression plots, you'll see that even that amp pushed those drivers quite close to their limits.


----------



## Ilkka

Wow! :bigsmile:


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## Sonnie

That has to be a record for the Shack... :hail:

EDIT: As high as 278 at one point.


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## Mark Seaton

Ilkka said:


> Hi Mark, and thank you! :hail: I would be honoured to measure some of your creations. Though I'm 100 % sure even they won't defy physics, but still. :sarcastic:


I'm all about working _with_ the physics of the situation, not defying them.  As your testing confirms, there still remains plenty of room to keep pushing toward physical limits of performance within a given package/power/cost/whatever.

I think testing like you've done is important to exemplify that there are few, if any, all-dominant designs. Each design will have its strengths. The more interesting debate comes into play when we look at what different strengths will tend to deliver subjectively. Of course too many readers are looking for a clear winner to save them any debate on what to buy. :sarcastic:


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## anidabi

Now, just post the link to the AVS foorum and let's see how many will be viewing after that! 

BTW, nicely hijacked my post. :R


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## Sonnie

lol... I doubt a link at AVS to here would last long.


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## crackyflipside

:clap:

Thank you Ilkka!

Link was posted on AVS long enough to get a good conversation started. I removed it later as to not anger any mods there. Which is quite ridiculous if you ask me, we are sharing data that is all.


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## Ilkka

Sonnie said:


> That has to be a record for the Shack... :hail:
> 
> EDIT: As high as 278 at one point.


Actually it went over 300. :bigsmile:


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## crackyflipside

Now is that counting unregistered users also?


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## Sonnie

Yeah... I think it does.


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## SteveCallas

You've done it again Ilkka, great job :clap: You truly are THE source - HTS is lucky to have you. In my eyes, you've taken your testing to the next level by incorporating some of the popular DIY players, exposing just how much more performance they offer for the enthusiast's dollar. A lot of us knew it before, but this puts it out there in black and white objectively for all to see. There isn't anybody else out there that I know of doing anything like that - the professional reviewers are too scared to and other enthusiast reviewers aren't nearly as knowledgeable or capable as you are. Excellent work :T

I'm also happy to see that after nearly two full years of debate, measurements put the nails in the coffin (where common sense and logic failed) regarding the performance advantage of a LLT type design. There will likely be even more interesting debates to come (like using a 60hz crossover with large diameter drivers as opposed to 80hz - something I decided to do after a discussion you and I had ), and I look forward to partaking in all of them on this forum, but now at least we can move past the lowest denominator of factless denial. I thank you greatly for that :hail:

Are we free to post comments for each sub, or would you prefer we didn't?


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## soho54

Ilkka, nice set. I don't know what else to say that hasn't already been said. Thank you. I know this took an incredibly large chunk of your time the last few months, and hopefully not too much money. Your efforts are most appreciated.

I have seen/done several DIY FR graphs, but it was really nice to see all the extras. The devil is in the details. :cunning:



> I'm also happy to see that after nearly two full years of debate, measurements put the nails in the coffin (where common sense and logic failed) regarding the performance advantage of a LLT type design.


Ahh, now you are going to have to listen to, "But how does it sound? A graph can't tell you that. A flat FR that goes on for days isn't everything. Harmonic distortion, group delay, spectral graphs? Who can understand those anyway? It all changes in-room, so who care what the sub does on it's own?" :blink: :rolleyesno: That was sarcastic, for those who are wondering. :R

I love all the new guys that like to brag about how they don't use any models to design a sub. :coocoo:



> There will likely be even more interesting debates to come (like using a 60hz crossover with large diameter drivers as opposed to 80hz - something I decided to do after a discussion you and I had )


Was this public? You don't pick the xover based on the sub system? PM me.


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## Mark Seaton

SteveCallas said:


> There will likely be even more interesting debates to come (like using a 60hz crossover with large diameter drivers as opposed to 80hz - something I decided to do after a discussion you and I had ), and I look forward to partaking in all of them on this forum, but now at least we can move past the lowest denominator of factless denial. I thank you greatly for that :hail:


Hi Steve,

I could be wrong, but I suspect your mention of crossover frequency and driver diameter is a mis-diagnosis of the problem. There can certainly be issues with drivers at higher crossover frequencies (60-120Hz), but it is rarely, or at best indirectly, due to cone diameter. What effects are you specifically referring to?


----------



## Mark Seaton

SteveCallas said:


> I'm also happy to see that after nearly two full years of debate, measurements put the nails in the coffin (where common sense and logic failed) regarding the performance advantage of a LLT type design.



This is somewhat of a cross post, but this discussion belongs here...

Steve,

I'm glad the rose colored glasses are working so well. :sarcastic: 

There are many things that can be seen in Ilkka's measurements. They do clearly show the observed upper bass shelving that the higher inductance motors have, and the distortion effects above that corner. Compare the Tumult or TC2k drivers to the XLS 12" within it's limits. Power compression in the different designs show predictable differences. The Tumult shows that distortion is higher down low in the sealed designs, but doesn't have to be astronomically so. The 270L TC 2k matched up with models exactly in frequency response, inductive corner and all. The fast rise in distortion below tuning is also clearly shown, confirming that you do want to be aware or cautious of what gets input below ~15Hz, particularly as you can see the simultaneous compression onset. We also see that above 40-50Hz, the TC2k will face compression at higher levels, again easily expected/predicted. The LLT is a very good performer overall, but it's also a lot of space for the given performance.

Indeed, some have made a much bigger deal out of alledged shortcomings than is warranted, but you can also clearly see the in-band, good and bad effects of the LLT's resonant anomaly just above 150Hz in the form of distortion drop and peak around 75-90Hz. I'm not saying this makes it good or bad, just that there are real effects that many like to skim past.

I guess since it would cost more, you would find nothing interesting or impressive in mostly equalling, and in some ways bettering, the LLT's performance in less than 70L internal with 1000W (no, not any current product). :sarcastic:


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## brucek

> The LLT is a very good performer overall, but it's also a lot of space for the given performance.


Well put. That's the rubric that says it all in my little head. If you got the space, it performs well.



> I guess since it would cost more, you would find nothing interesting or impressive in mostly equalling, and in some ways bettering, the LLT's performance in less than 70L internal with 1000W (no, not any current product).


I'd be interested in hearing about it... 

brucek


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## Mark Seaton

Another interesting observation that doesn't align with "common knowledge" about the vented subs in the test. Start looking through the charts and frequency responses vs. distortion at different frequencies. You will see that the distortion minimum does NOT align with the tuning frequency. :scratchhead:

In fact, the distortion minimum tends to fall near the transition point of the port and driver handing off the workload...


----------



## Mark Seaton

brucek said:


> Well put. That's the rubric that says it all in my little head. If you got the space, it performs well.


Agreed. I've never said it's a bad way to go, but hardly the only.



> I guess since it would cost more, you would find nothing interesting or impressive in mostly equalling, and in some ways bettering, the LLT's performance in less than 70L internal with 1000W (no, not any current product).
> 
> 
> 
> I'd be interested in hearing about it...
> 
> brucek
Click to expand...

About all I want to say at this point is that the hardest part is fitting everything in that little box! :scratchhead:


----------



## brucek

> About all I want to say at this point


No fair.... onder:

brucek


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## Blaser

Mark Seaton said:


> Hi Mark.... I am delighted to see you post here as your posts are always benefical to each and everyone (at least the "subwoofers nuts" like me)...Thanks for your input!!
> I have only 2 self -explanatory comments below...
> 
> 
> 
> I'm glad the rose colored glasses are working so well. :sarcastic:
> 
> 
> 
> Are they really "Rose coloured glasses"??:rolleyesno:
> 
> 
> 
> The 270L TC 2k matched up with models exactly in frequency response, inductive corner and all
> 
> Click to expand...
> 
> Is it really "and all"?:sarcastic:
> 
> Thanks!
Click to expand...


----------



## soho54

What is this "common knowledge," you speak of? :huh:

You can look at his old tests and see the same things. In a ported system just like a sealed one, the driver has a low distortion point after which distortion sky rockets. In a ported system this distortion increase is slowed, and results in a new low spot right around the tuning. After this second low the port increases distortion at an accelerated rate as you go down in frequency.

Distortion is at lower levels down until a little after the tuning frequency in a ported box using the same driver, as it would produce in a sealed enclosure.

The real question is what difference does distortion make at sub 15Hz frequencies at levels above 100dB? This is where we need listening tests post haste. Who wants to be deaf? :R

I know the two single TC subs are not the same, but they are close enough to get some wheels turning. Compare their distortion graphs to one another. It is an interesting comparison. 

Note: the ported one needs more dampening on its end caps to kill that 75Hz resonance. It can be done. :yes:


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## SteveCallas

Wow Mark, wow :daydream:



Mark said:


> They do clearly show the observed upper bass shelving that the higher inductance motors have, and the distortion effects above that corner


What exactly does that have to do with the LLT type design? This is purely a function of the driver, as it is observed in both the ported and sealed TC2k subs. I guess you missed that though.



> The Tumult shows that distortion is higher down low in the sealed designs, but doesn't have to be astronomically so.


Let's keep things fair and on point. You want to compare the sealed Tumult to the TC2k LLT, yet you are overlooking the obvious, most direct, and most significant comparison - the TC2k LLT vs the sealed TC2k. The distortion differences below 40hz are large Mark, *very large*. Not only is the distortion much lower with the LLT, it's much lower with much stronger, flatter, sustained low end output. I guess you missed that though.

If there were a Tumult LLT, the differences would be just as large.

Also keep in mind that for any sealed sub, including the Tumult, yes, distortion does have to be "astronomically" high in comparison to an equivalent number of drivers in a LLT if you want to match the capabilities of the LLT. There is a 15db drop in the FR of the sealed Tumult from 40hz to ~15hz, and this requires EQ boosting to bring it up. It takes exponentially greater excursion to boost lower frequencies, so for as bad as the distortion is ala natural, it's nothing compared to how cranked it will be after ~10db of low end gain, which is what would be needed to mach the LLT. I guess you missed that though.



> We also see that above 40-50Hz, the TC2k will face compression at higher levels, again easily expected/predicted.


We also see that the LLT flavor has a constant 2-3db clean headroom advantage over the sealed above 40hz in addition to the monstrous clean headroom advantage down low. ****, it has the clean headroom advantage at EVERY frequency, even below tuning. It even has more clean low end headroom than the dual driver sealed sub. I guess you missed that though. 

I didn't see any mention of the "poor" transient response that you and bosso loved to mention would undoubtedly accompany such a sub. Or how about your comment that output compression occurs in roughly any size diameter port above 10m/s? What about the comment that a LLT tries to mesh a sealed and ported, yet reaps none of the benefits of either? 

Come on Mark, let's get real at least once in these two years I have been talking subs with you. The LLT is a better sub in all regards. It has the flatter, deeper FR with stronger sustained low end output that meshes better in average rooms than sealed with no EQ boosting needed. It has a monstrous distortion advantage naturally that is even more exagerrated when you factor in the EQ boosting typcally needed and desired with sealed subs. It has the clean headroom advantage at every single frequency tested, ranging from 2db all the way up to 11db. Group delay is the same as sealed all the way until below tuning, at which point it is still well under one cycle and *absolutely* a non issue. Add in some EQ boosting to the low end of the sealed sub and watch that group delay jump.

These are not small differences Mark, these are quite large. One sub is clearly better than the other, and based on the DIY projects built over the last two years, yes, it does warrant the larger size. Don't seem to be very many people who take issue with the size.....only the ones who still believe sealed is superior :heehee:

You're a nice guy and I have enjoyed the debates over the last two years. Please just stop with the denial though - the rose colored glasses comment is ironic at best :T


----------



## cixelsid

It's an apples vs oranges situation to compare a 270L EBS vs a 90L sealed alignment. Accurate performance comparisions occur only when the enclosures are of equal size.


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## bobgpsr

Mark Seaton said:


> I guess since it would cost more, you would find nothing interesting or impressive in mostly equalling, and in some ways bettering, the LLT's performance in less than 70L internal with 1000W (no, not any current product).


Does it involve Passive Radiators?


----------



## Ilkka

SteveCallas said:


> We also see that the LLT flavor has a constant 2-3db clean headroom advantage over the sealed above 40hz in addition to the monstrous clean headroom advantage down low. ****, it has the clean headroom advantage at EVERY frequency, even below tuning. It even has more clean low end headroom than the dual driver sealed sub. I guess you missed that though.


I believe we already discussed about this soon after those measurements? The 90L sealed TC-2000 had probably an off-spec driver. No simulation shows that kind of frequency response in 90L enclosure, or the upper bass max SPL difference compared to the 270L ported enclosure. It probably has somewhat heavier cone/VC which gives it lower sensitivity. So therefore the difference in upper bass max SPL was larger than it should be. With two identical drivers, the smaller sealed should have around 0.5 dB more upper bass sensitivity/max SPL capability than the larger ported one.


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## bobgpsr

SteveCallas said:


> Wow Mark


A nice friendly technical debate does not need adjectives about the color of glasses, etc. I don't read the various posters as being in denial but rather taking the devil's advocate -- point -- counterpoint -- positions in a discussion of trade-offs in subwoofer design approaches. It is great to have such a high caliber of technical discussion but we do not want emotionally charged phrases to be used at Home Theater Shack.

Thanks.


----------



## soho54

So it was more "Accurate" to compare two subs distortion levels with completely different drivers in a 270L vented and 100L sealed enclosures in your opinion? Neither were scientifically accurate to the tenth degree, but do they really need to be?

Besides how real world is it to throw a TC2K into a 270L sealed box? What would this tell you anyway? The only knock with the comparison is that one was a SVC 4 ohm and the other was DVC 2x4 ohm, and TC's lax quality control.

Look at the harmonic distortion levels between the two single TC subs and the Tumult at 105dB. Then by % By Component. Check out the SD charts now. We know a ported system rings below tuning, so concentrate on the area above the tuning. (I'm not to worried about ringing below 15Hz, are you? If it was tuned to 25Hz I would be singing a different tune. :R) Check out the IM charts at 90dB and 100dB. Now what conclusions can you draw? Go back and add an SVS and HSU to the mix. Hmmm... 

To really get an idea of total distortion you would need to compare harmonic, intermodulation, and phase distortion. I'll stop here.

EDIT: Spelling & clarification.


----------



## Mark Seaton

Hi Steve,

I have limited time today, but wanted to make a few points. I'll have to come back later for others.



SteveCallas said:


> Wow Mark, wow :daydream:
> 
> 
> 
> Mark wrote:
> They do clearly show the observed upper bass shelving that the higher inductance motors have, and the distortion effects above that corner
> 
> 
> 
> What exactly does that have to do with the LLT type design? This is purely a function of the driver, as it is observed in both the ported and sealed TC2k subs. I guess you missed that though.
Click to expand...

I didn't miss it at all. It is clearly observed in the TC & Tumult motors. Many have claimed this doesn't matter. It's effect is clear on sensitivity and distortion. I was in no way saying this only applies to vented subs. It does apply to the predictions made in modeling. Fortunatley UniBox now includes a more detailed modeling ability if we are given an impedance curve or the exact data. Recall that it did not always have this capability.



> Let's keep things fair and on point. You want to compare the sealed Tumult to the TC2k LLT, yet you are overlooking the obvious, most direct, and most significant comparison - the TC2k LLT vs the sealed TC2k. The distortion differences below 40hz are large Mark, *very large*. Not only is the distortion much lower with the LLT, it's much lower with much stronger, flatter, sustained low end output. I guess you missed that though.
> 
> If there were a Tumult LLT, the differences would be just as large.


I didn't say I was directly comparing one to the other. I'm not arguing that a large vented box will be louder. You're the one hung up on driver:driver comparison. I'm looking at the characteristics of each design. The sealed design is much more dependent on the linearity of the driver. The Tumult sub is a good example of reasonable distortion output below the inductive corner. The strengths that will make for a strong "LLT" and a strong sealed sub will be different. I'm sure you'll see it differently than I do, but I guess that's what keeps these discussions going. :sarcastic:



> Also keep in mind that for any sealed sub, including the Tumult, yes, distortion does have to be "astronomically" high in comparison to an equivalent number of drivers in a LLT if you want to match the capabilities of the LLT. There is a 15db drop in the FR of the sealed Tumult from 40hz to ~15hz, and this requires EQ boosting to bring it up. It takes exponentially greater excursion to boost lower frequencies, so for as bad as the distortion is ala natural, it's nothing compared to how cranked it will be after ~10db of low end gain, which is what would be needed to mach the LLT. I guess you missed that though.


Distortion / SPL output does not change with EQ. Yes, as agreed above, the higher order, vented system will have more output per driver. A 6th order bandpass will have more output in an even larger box with less power, and a horn or higher order bandpass could be made to have even greater output. I'm not saying a big vented box is useless. I'm designing BIG custom bandpass subs with vented low frequency sections. They have their uses, especially when the listening area is large and you have lots of space available.



> I didn't see any mention of the "poor" transient response that you and bosso loved to mention would undoubtedly accompany such a sub. Or how about your comment that output compression occurs in roughly any size diameter port above 10m/s? What about the comment that a LLT tries to mesh a sealed and ported, yet reaps none of the benefits of either?


Group delay is almost exactly as modeled. Below 15Hz it continues to rise. Yes, it stays below 1 cycle. A sealed box EQ'd for a 2nd order LF roll off will have lower group delay, dependent on a few factors, but we need to be careful as inductance skews the group delay comparisons.

So far as the 10m/s note, I suggest you review the data. It appears the real tuning of the 270L sub is closer to 15Hz from eyeballing the response. My models show about 10m/s air speed at roughly 98dB @ 2m/15Hz. That seems to match up prett well with the onset of compression in the "105dB" sweep.

A big difference in how we probably are viewing things comes down to what they translate to in real use. While no secret, we need to remember that real content is not single frequency components, but rather a spectrum of frequencies, which could even be viewed as a shaped noise spectrum. While most measurements examine sinusoidal behavior (appart from Ilkka's multi-tone tests), non-linearites cause by any one component or sum of components will often affect all others being produced at the same time.


----------



## Ilkka

Mark Seaton said:


> It appears the real tuning of the 270L sub is closer to 15Hz from eyeballing the response. My models show about 10m/s air speed at roughly 98dB @ 2m/15Hz. That seems to match up prett well with the onset of compression in the "105dB" sweep.


I have measured the real tuning, and it's ~16.5 Hz.


----------



## Mark Seaton

Ilkka said:


> I have measured the real tuning, and it's ~16.5 Hz.


Thanks for the correction Ilkka. That puts the maximum vent velocity right about 15Hz, and moves the modeled point of 10 m/s air speed somewhere above 96dB @ 2m gp @ 15Hz. Real world losses mean that air speed will be a little lower than predicted with a little more driver contribution, so the 10 m/s onset of compression still looks about right. Even more interesting is that even at 10Hz the predicted excursion should be less than +/-20mm, and less than +/-15mm above ~12Hz, suggesting the compression observed is not entirely dependent on the driver excursion. Of course this verifies that the realm where ports work their best are when the box and port are large enough to keep required vent velocity down.

That's not to say ports aren't plenty useful past 10 m/s air-speed, but most implementations do begin to change behavior beyond that point.


----------



## SteveCallas

bobgpsr said:


> It is great to have such a high caliber of technical discussion but we do not want emotionally charged phrases to be used at Home Theater Shack.


I'm sorry bob, won't happen again. After being told I was wrong for two years by a select group of people with nothing but sarcasm and "because I say so" to back it up when I knew I was precisely right, I found these results extremely satisfying. To then hear nitpicking about things not even related to the alignment itself, but the driver, when we can clearly see how superior the LLT is to the sealed sub, well, I'm proud of myself for keeping it as polite as I did :bigsmile: I do apologize though.



Mark said:


> You're the one hung up on driver:driver comparison.


Correct, I am, same as I have been since day one. I'm looking to optimize the performance from a given driver without spending a ton on "accessories", cause that money could instead be put to MUCH better use buying more drivers. 



> Distortion / SPL output does not change with EQ


The single driver sealed subs appear to have a little more output to give on the low end with some EQ - the distortion will grow exponentially if you do that though.



> Yes, as agreed above, the higher order, vented system will have more output per driver.


More *clean* output, flatter FR, deeper extension, and lower distortion per driver, yes.



> A 6th order bandpass will have more output in an even larger box with less power, and a horn or higher order bandpass could be made to have even greater output


Build a 6th order bandpass using a single TC2k for no more than 125% of the cost of the LLT (US dollars) and measure it the way Ilkka has. If you can extract as much balanced performance as the LLT, I'll give you $5. Same for the horn. :newspaper: 



> A sealed box EQ'd for a 2nd order LF roll off will have lower group delay, dependent on a few factors, but we need to be careful as inductance skews the group delay comparisons.


The only problem is that now you have a second order rolloff. Being 12db down at 20hz isn't what most people seem to be after, and it's definitely not worth some millisecond difference in group delay in subsonic, inaudible frequencies.



cixelsid said:


> It's an apples vs oranges situation to compare a 270L EBS vs a 90L sealed alignment. Accurate performance comparisions occur only when the enclosures are of equal size.


I don't know too many sealed enthusiasts who would suggest using that driver in a 270 liter sealed enclosure. When people buy a high excursion driver for a DIY HT sub, the choice they usually face is small sealed or LLT nowadays. Ilkka's testing compares just that scenario.


----------



## cixelsid

SteveCallas said:


> I don't know too many sealed enthusiasts who would suggest using that driver in a 270 liter sealed enclosure. When people buy a high excursion driver for a DIY HT sub, the choice they usually face is small sealed or LLT nowadays. Ilkka's testing compares just that scenario.


If your exposure to DIY subs is limited to those posting on internet forums that's a narrow slice of the DIY demographic. For decades people have put drivers in large sealed boxes when the goal is sound quality over higher output.


----------



## SteveCallas

Using a larger sealed enclosure with the same driver will get you a little bit more low end sensitivity, a little bit less low end distortion, and a little bit better impulse response. What you lose is low end protection from bottoming, thus a bit more headroom as well. I've mentioned all this in my "LLT Explained". Either way you look at it, the ported option is much more attractive performance-wise.


Ilkka - many of your pictures are down, just a heads up.


----------



## Exocer

Its great to have these results up Ilkka. I particularly found the comparison between the Tumult MKI and TC-2000 sealed subs interesting from a THD standpoint. It was shocking to see the TC-2k shoot past 20% THD at 20hz (110db) while the Tumult, at the same SPL level, seemed to remain under 15% thd. :unbelievable:

That being said, I really look forward to you receiving the new Css and LMS driver to compare the more recent XBL^2 driver with its older "relative" as well as how the two linear motor topologies compare from a purely objective perspective.:T


----------



## Ilkka

SteveCallas said:


> Ilkka - many of your pictures are down, just a heads up.


I know. The server was updated last night. Now they should be ok.


----------



## Ilkka

http://www.hometheatershack.com/forums/subwoofer-tests/

I have put some older results (round 1 and 2) back on-line. I have also created an index for easier browsing/searching.


----------



## Magnus_CA

Ilkka,

Is it safe to assume the Velo SPL-1200r is not going to get a chance to stretch its legs on your testing lot?

I've done some searching and haven't found an answer to this yet.


----------



## Ilkka

Magnus_CA said:


> Ilkka,
> 
> Is it safe to assume the Velo SPL-1200r is not going to get a chance to stretch its legs on your testing lot?
> 
> I've done some searching and haven't found an answer to this yet.


Most probably there will be one more session this fall. If someone brings that Velo in, I will gladly measure it. Hopefully the guy who cancelled last time will be able to come this time.


----------

