# Battle of the Monsters



## funky_waves (Jul 3, 2007)

Measurements to follow, initial impressions. The Acoupower definitly gives the LMS a run for the money, first few min of listening, upper to mid bass seems to sound better, low stuff seems to be as good. The Acoupower can realy move some air!! a lot more so than you think just by looking at it.

The RE XXX will be in testing ASAP, should be under a week.


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## Guest (May 24, 2008)

next time i pass through sechelt im going to drool all over those.
well, iv already drooled on a few.
infact i bought a few, hehe


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## vinculum (Feb 13, 2007)

funky_waves said:


> Measurements to follow, initial impressions. The Acoupower definitly gives the LMS a run for the money, first few min of listening, upper to mid bass seems to sound better, low stuff seems to be as good. The Acoupower can realy move some air!! a lot more so than you think just by looking at it.



What alignment cabinet is your Acoupower in? Sealed? Better mid to upper bass than the LMS and equal lows. I'm happy to hear that! :yay:

I've had my drivers since January and I still don't have boxes built! I just did a free air test the other week. You can see videos of the test on youtube. But they aren't terribly exciting to watch. And I'm currently doing a fan mod on a couple CE4000's to drive them with. Boxes will be next!

I'll certainly be interested to hear and SEE anything Acoupower related that you want to post!

Dr V


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## funky_waves (Jul 3, 2007)

I put it in my LMS enclousure, 340L tuned to 16hz so I cant compare them side by side but I am very impressed.


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## Ricci (May 23, 2007)

Sweet! I didn't know you had an Acoupower Nathan. I'm looking forward to your impressions of the XXX and the Acoupower compared to the LMS.

Bring on the testing!!!:bigsmile:


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## funky_waves (Jul 3, 2007)

Blue line is Acoupower the other line is LMS5400. No EQ at LP in 900 square foot room with 8-11foot vaulted ceiling.


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## Blaser (Aug 28, 2006)

WOW, pretty impressive that blue curve. Any idea on the pricing?


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## vinculum (Feb 13, 2007)

funky_waves said:


> I put it in my LMS enclousure, 340L tuned to 16hz so I cant compare them side by side but I am very impressed.


The ACP could probably use more volume than the LMS, but the results are impressive nonetheless. I'm not familiar with your LMS box. Whats the vent configuration?

Dr V


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## funky_waves (Jul 3, 2007)

vinculum said:


> The ACP could probably use more volume than the LMS, but the results are impressive nonetheless. I'm not familiar with your LMS box. Whats the vent configuration?
> 
> Dr V


It has dual 6" large flare ports.


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## mdrake (Jan 31, 2008)

WOW very impressive!!! Pricing in located here.


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## vinculum (Feb 13, 2007)

Ahhh.. I see now.. You put it in your custom sonotube.


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## funky_waves (Jul 3, 2007)

I did a couple tests today on the Acoupower and LMS5400, for maximum output before audible distortion, I also measured the mechanical cone travel, on all three, up to the point where the suspension really starts to stiffen up/become non linear. The LMS5400 is 65mm p-p the Acoupower is 64mm p-p, and the REXXX is 82.5mm p-p.

Acoupower did:
105.6db @10Hz
114.4db @15Hz
125.5db @20Hz
118.7db @25Hz
117.7db @30Hz
123.7db @ 40 Hz (amp limited)

LMS5400 did:
105.4db @10Hz
119.4db @15Hz
126.3db @20Hz
116.9db @25Hz
115.4db @30Hz
123.7db @ 40 Hz (amp limited)

Measurements where taken at 5 feet from the sub in the corner with a pure sine wave, turned up until distortion is heard then down till it’s gone and a reading taken.

The icing on the cake as it were, the Acoupower is 8ohm so only has 2500rms available, vs. 3600rms for the LMS5400


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## vinculum (Feb 13, 2007)

Very comparable. The LMS ramped up sooner @ 15 Hz, probably due to its lower Fs being closer to tune. 

I assume there were no problems with vent noise and the Acoupower?

Thanks for sharing.
Dr V


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## funky_waves (Jul 3, 2007)

I have been pondering the results, and have a theory:nerd:. At tuning there is some port noise, but with real world material I have never heard any port noise with either driver. But! At 15hz the amp is not clipping, the driver is not at max travel, and there is some port noise, so perhaps the limiting factor near tuning is port compression(the noise is low due to the large flares but compression still may be occurring) Why the Acoupower compresses the ports at a lower level is interesting, maybe it is a good thing(drives the ports harder as Carlos claims), maybe with larger ports it would benefit more.:scratch: might just have to build another box to test theory.

Ps, I ran the ts parameters on the acoupower, I have not seen many, if any, drivers measure better than published specs, some very very close, but most often drivers measure with a higher Fs, Qes, and Le. It therfore models a tiny bit better for low end.

Published:
Fs: 28.2hz
Re: 6.2
Qms: 8.9
Qes: 0.62
Vas: 174L
Le: 1.2mH

Measured
Fs: 24.9hz
Re: 6.16ohm
Qms: 4.18
Qes: 0.59
Vas: 177L
Le: 0.72mH

I also ran the ReXXX, the more typical higher Fs and Qes, it is not fully broken in however, so the Fs may go down slightly and the Vas up slightly. 
Published
Fs: 15.6hz
Re: 4.2ohm(coils series)
Qms: 2.82
Qes: 0.68
Vas: 482L
Le: N/A

Measured
Fs: 17.5hz
Re: 4.39ohm
Qms: 6.2
Qes: 0.83
Vas: 296.5L
Le: 3.88mH


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## Ricci (May 23, 2007)

Great thread Nathan and thanks for the test data. I don't know of anyone else who has these 3 driver's and the ability to test them. 

Looks like the Acoupower is no paper tiger (Good news eh Dr V!). I think you may be right about the port compression but it does seem weird that it would limit so much earlier than the LMS at 15hz. especially since it's a solid match at 10hz. I really hope Illka tests one of these.

Could you email me your WFT3 test data for my XXX? It would save me from testing it myself. I did test my other one and it was similar to what you got. FS was 17.6 on that one. QE and QMS were similar also. 

Seems like a good xmax figure for the Acoupower's is around 30mm one way. 82.5mm p-p xmax on the XXX:jiggy:? Hey it may not be the 108mm claimed but it's still quite ridiculous:R. 

Awesome stuff!


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## noah katz (Jun 8, 2007)

Thanks, Nathan, finally some 3rd party measurements of the Acoupower.

"might just have to build another box to test theory."

Or plug the ports.

I'm a bit puzzled by something - if the 24.9 vs. 28.2 Hz Fs is due to less compliance and not more mass, the Vas would be 28% higher than spec.

"the Acoupower is 8ohm so only has 2500rms available, vs. 3600rms for the LMS5400"

Just to be clear, you're saying the ACP's similar output was achieved with 2500 vs 3600 W, right?


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## funky_waves (Jul 3, 2007)

I may plug the ports and retest both drivers when I get some time.

Yes the Acoupower had simmilar output with over 1000watts less!!

Note about the cone travel, my measuerments are just manual to compare driver to driver, when under power all three drivers move about 5-10mm more each way before distortion.


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## funky_waves (Jul 3, 2007)

RE XXX max ouput:

118.6db @10Hz WOW!!
120.4db @15Hz :bigsmile:
124.0db @20Hz 
114.5db @25Hz
114.2db @30Hz
117.7db @ 40 Hz (amp limited)


Little less above 15hz but below! felt like my ears were going to bleed when testing it at 10hz

Red, REXXX
Blue, LMS5400
Purple, Acoupower


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## Ricci (May 23, 2007)

Just like I thought. The Acoupower and LMS have more output and sensitivity up high, but the XXX brings the pain on the really low stuff. Thanks for these tests Nate! It appears that all 3 drivers are true beasts. Looks like the lower readings at 25 and 30hz are partially due to your room, since it affects all 3 drivers.

How about some comments on the XXX powerport system? It appears as though it works as suggested eh? 11hz tune check...gargantuan low freq output...check. Did you hear any bad noises or chuffing? Think it compressed on that 10hz spl test? I must say I'm feeling:jump:.

118.6db at 10hz I think that legitimately calls for this one:hsd:


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## funky_waves (Jul 3, 2007)

The port system seems to work as predicted I don’t recall hearing anything from the port. Although to be honest I did not pay close attention to it. I will do some more listening. 

For real world material there is defiantly no noise at all, even my LMS enclosure with either the LMS or the Acoupower has no problems with real material, only with pure sine waves.

So far I think I prefer the Acoupower for music, the XXX for movies and the LMS for both. This seems to correlate with the max output numbers. 

To use some "bad" subwoofer terms; the Acoupower is the "tightest", the XXX the "softest", but very weighty in the low end and the LMS is somewhere in-between for both aspects. None of them seem "slow", "boomy" ect.

All three are defiantly in the same league with each having there strong points. I think the Acoupower and the LMS are very close as do the people who have heard both. One person prefers the LMS but is not sure why, I am yet undecided. The XXX is the best at making it feel like a track hoe is trying to shake the building down, the other two maybe a smaller track hoe. The only "bad" thing about the XXX is that to really get the best out of it you need around 20cubic feet, whereas the LMS and Acoupower work in substantially smaller enclosures.


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## Ricci (May 23, 2007)

That's about what I expected. 
Acoupower for music
XXX for HT
LMS splits the difference.
None of them really being "bad" in either application.

Is the Acoupower yours? If it is, I am guessing that you will build it it's own dedicated enclosure. Any ideas on what you might go with for it yet?


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## funky_waves (Jul 3, 2007)

I did some tests at 11 and 12hz and the amp clipped at about 116db, that is likely due to the fact that that is where minimum impedance occurs. There is some air noise from the port but not much at all. Defiantly a ton of air moving!


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## funky_waves (Jul 3, 2007)

Ricci said:


> Is the Acoupower yours? If it is, I am guessing that you will build it it's own dedicated enclosure. Any ideas on what you might go with for it yet?


I got it to try out, I have a couple ideas, one I realy want to do, but it would be heavy:bigsmile: I will likely biuld a smallish sealed enclosure for it. 20"cube maybe.


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## Ricci (May 23, 2007)

That's good to hear about the port noise. I don't think I'll be listening to many 116db 11hz sine waves:yikes:. It probably won't be an issue for program material then. Man I've gotta ask... what does that kind of output at those frequencies sound like? Is it like a train going by, is everything rattling in your room or what? 


This heavy Acoupower enclosure idea...that wouldn't be an aluminum one would it:cunning:? I vote :yes:


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## vinculum (Feb 13, 2007)

An aluminum enclosure would make that Acoupower driver the ultimate "cool" subwoofer! Talk about low thermal compression, you could really crank the juice!


Wonder what those enclosures would cost.... :scratchchin:


Dr V


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## Bob_99 (May 8, 2006)

Could someone explain to me why aluminum would make a better enclosure? Is it because it is less flexible (assuming thick enough aluminum)?

Thanks

bob


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## vinculum (Feb 13, 2007)

I was thinking mostly about the transfer of heat the driver produces when asked to dissipate a few kilowatts in a sealed box. The basket could transfer heat to the mounting area given a thermally conductive sealer, and the backwave could blow directly on the aluminum like a gigantic heatsink. This along with the Acoupower driver's efficient heat wicking pole vent and 5 cubic feat of heatsink around the basket would be a winner me thinks.

Dr V


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## Ricci (May 23, 2007)

Plus it would just look cool.

Dr V.,
Did you ever decide what you are going to do with your Acoupower's? I'm guessing that maybe you are holding out for Illka's tests to help decide what to do:sneeky:?


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## Bob_99 (May 8, 2006)

Very interesting!

Thank you for the explanation.

Bob


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## vinculum (Feb 13, 2007)

Ricci said:


> Plus it would just look cool.
> 
> Dr V.,
> Did you ever decide what you are going to do with your Acoupower's? I'm guessing that maybe you are holding out for Illka's tests to help decide what to do:sneeky:?


As soon as I think I have the alignment nailed down, I'm considering something else! I was working on the amplifier selection not long ago.

I'd like to see it test of course, but I think thats a long time away for Illka to get a driver. Last I heard communication between the two has been sparse.

I'm glad to hear Nathan's impression of the ACP as being "tight". This puts more weight on considering a reflex alignment. I definitely want a tight sound. Moreover I don't want to be underwhelmed with my upgrade.

I've got lots of other considerations as well that I won't get into just yet.

One of these days soon I'll jump in and start cutting... 

Dr V


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## TheEAR (Jan 15, 2008)

Most impressive ! The RE XXX 18" is a monster,it moves air like no other,I am impressed to the point of getting two of these sick drivers.


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## Blaser (Aug 28, 2006)

funky_waves said:


> I did a couple tests today on the Acoupower and LMS5400, for maximum output before audible distortion, I also measured the mechanical cone travel, on all three, up to the point where the suspension really starts to stiffen up/become non linear. The LMS5400 is 65mm p-p the Acoupower is 64mm p-p, and the REXXX is 82.5mm p-p.


WOW How did you measure that? :bigsmile:


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## Ricci (May 23, 2007)

TheEAR said:


> Most impressive ! The RE XXX 18" is a monster,it moves air like no other,I am impressed to the point of getting two of these sick drivers.


Copycater:hissyfit:! JK Arthur. Maybe a pair in 9ft sealed each with some Itech8000 voltage???

Monster is the right term for the XXX though. I'm still trying to get a good imagining of what 118.6db at 10hz sounds like:daydream:. I've never heard bass like that. Maybe some solid high-output 16hz stuff but nothing that heavy at 10hz. I don't think my tired old Velodyne CT1500's will do that much output at 40hz. That's from 1 driver too.


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## funky_waves (Jul 3, 2007)

Blaser said:


> WOW How did you measure that? :bigsmile:


Just a simple manual measurment with a straight edge and a ruler, just to see how the suspention travel compared for the three drivers, they do stretch 5-10mm more in each direction when under power, so they all seem to have there respective claimed mech travel.


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## ISLAND1000 (May 2, 2007)

Great work Nathan and very usable listening impressions.
It looks like the loss of the LMS doesn't mean the "ultimate DIY sub driver" is history.
The XXX and the ACP are just as adequate for what we need! Lets get busy and get these two amazing drivers some place to vibrate . . . . . Vinculum . . . . EAR?


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## Ricci (May 23, 2007)

I don't know. There still isn't a big uber 18 for the small sealed boxes or PR'd enclosures. That was what the LMS did well and there is not really a replacement for that yet. The Acoupower is more suited to mid-sized alignments(for an 18) and the XXX for large enclosures. Neither are going to rock in 100L quite like the LMS will. The Acoupower would be better in 200L and the XXX in 300L, or thereabouts.


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## ISLAND1000 (May 2, 2007)

Using WinISD take a look at the performance of (2) XXXs in a 6 cu. ft. sealed box with a Linkwitz Transform with the Fo set @ 40 and the Fp [email protected] 15.
I know that's not a 100L but it's a manageable size.


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## anidabi (Jun 10, 2007)

I have to say this that there is some really interesting stuff going on.  Great work Nathan, since you have the skills and the equipment, can you take a nearfield measurements from the drivers at hand? It would be nice to see how low the Le in acoupower really is.




funky_waves said:


> I have been pondering the results, and have a theory:nerd:. At tuning there is some port noise, but with real world material I have never heard any port noise with either driver. But! At 15hz the amp is not clipping, the driver is not at max travel, and there is some port noise, so perhaps the limiting factor near tuning is port compression(the noise is low due to the large flares but compression still may be occurring) Why the Acoupower compresses the ports at a lower level is interesting, maybe it is a good thing(drives the ports harder as Carlos claims), maybe with larger ports it would benefit more.:scratch: *might just have to build another box to test theory*.





funky_waves said:


> I got it to try out, I have a couple ideas, one I realy want to do, but it would be heavy:bigsmile: I will likely biuld a smallish sealed enclosure for it. 20"cube maybe.


I guess that you have quite a lot work going on already, but bigger port effect and small sealed enclosure performance would be nice to see.


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## Ricci (May 23, 2007)

Anidabi,
Back on the first page Nate posted this from the WFT3 for the Acoupower
Published:
Fs: 28.2hz
Re: 6.2
Qms: 8.9
Qes: 0.62
Vas: 174L
Le: 1.2mH

Measured
Fs: 24.9hz
Re: 6.16ohm
Qms: 4.18
Qes: 0.59
Vas: 177L
Le: 0.72mH

0.72mh LE:1eye:

ISLAND1000,
I still have another XXX 18 that I will be going sealed with at some point. Were you saying 6ft for 2 of them? I'm thinking that I will do around 8ft sealed for my one. The problem is that the main claim to fame of the XXX is the HUGE displacement ability and it's almost impossible to get enough power to use most of it in a small sealed box. How much did you model it with in 6ft?


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## anidabi (Jun 10, 2007)

Hi Ricci! I saw that, but I was refering to proper graph where you can see it clearly. Like this:










and this:









http://www.hometheatershack.com/forums/subwoofer-tests/4652-lms-5400-buy-3.html#post51571



The numerical Le doesn't tell you in wich impedance model they have been measured(praxis, MLSSA, klippel). TC Sounds drivers have been measurured with praxis method and I believe that Exodus audio with klippel. Acoupower method I don't know. Unibox models with LR-2 method(don't know this stuff, just heared from Ilkka) and winISD does only a rough impedance modeling. So LMS Le parameter doesn't model right with unibox and in winISD Le is useless because it produces wrong FR. It's a bit messed up situation with different measuring methods and modeling programs. That's why I would like to see picture over some random number.


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## Ricci (May 23, 2007)

Nathan,
Are the Acoupower and the LMS the same mounting pattern and size? If so, maybe run the LMS in the 130L sealed box to compare against the Acoupower? 

Sidenote:I watched Finding Nemo last night with the XXX sub and the Darla tapping on the tank scene was :scared:! My girl was holding a glass of red wine and it was shaking in her hand. I love this sub man! Thank you!


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## ISLAND1000 (May 2, 2007)

I was just experimenting with that driver to see what box size and possible multiples of drivers would produce a similar power and FR similar to a LMS 5400 18".


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## Owen Bartley (Oct 18, 2006)

It's so nice to see that there are still some killer big drivers out there (not that I'll have the need for one any time soon). Having a few options at this level is going to lead to some really impressive projects, and I can't wait to see them as they roll in. Nathan, thanks for stepping up and comparing these monsters.


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## SteveCallas (Apr 29, 2006)

Ricci said:


> It appears as though it works as suggested eh? 11hz tune check


Hmm, if that's an 11hz tune, the enclosure is pretty undersized, as there is ~14db rolloff below 18hz.

Funkywaves, can you take a close mic measurement of the XXX sub?


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## funky_waves (Jul 3, 2007)

Steve,

I no longer have the XXX sub, so I can't take any more measurements, I was going to get a ground plane before it shipped but I ran out of time.

Take a look at these graphs comparing the FW18.1 ground plane and same enclosure in the same location as the XXX sub was in. If you look at 20hz and 10hz. There is a 16db differential from ground plane to in room, if you factor that in to the XXX sub it is down 17db at 10hz from 20hz, so in actual fact it is only down 1db at 10hz, this might be off a few db, Simulations predict around 4db down at 10hz, it is probably closer to that, but it gives an idea what is going on there anyway. 
My room has a very large resonance at 20hz that is causing that.


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## SteveCallas (Apr 29, 2006)

Ricci, can you take a close mic FR?


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## Ricci (May 23, 2007)

Steve,
I'm getting to it soon. I just got back from a business trip to HK last night and I have a lot of loose ends I need to tie up. I still need to give a review of the SDX subwoofer! I just fired up my new notebook today actually and I'm getting ready to download REW. Apparently someone lifted my Turtle Beach SC I ordered while I was gone:rant:, so I've got to iron that out too. I'll get to it hopefully within the next week or 2. Nathan had one of my XXX's. As he has noted the 25ft cab was tuned to 11hz roughly and this was confirmed with an impedence measurement and also through test tones. It should be around 3 to 6db down at 10hz and this seems to be the case, but I will definitly try to confirm concretely with measurements when I can.


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## Ricci (May 23, 2007)

Once I get REW running I'll take some FR measurements on the XXX enclosure. Here is the impedence curve that Nathan took with the WFT3. I also measured this and got a nearly identical reading. 

View attachment ReXXXbox impeadance.pdf


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## Ricci (May 23, 2007)

Here is a raw FR of the XXX at one of the primary listening spots.










here is a close mic of the driver...











How do I go about getting a good close mic response of the system? It's in room and the port and driver are separated. Do I just put the mic half way between the 2? What level?


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## Itay (Jul 14, 2006)

your suppose to measure each separately (close mic) and then "sum" both (in a nutshell)


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## Ricci (May 23, 2007)

How would I go about summing the 2 responses together in REW?


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## Itay (Jul 14, 2006)

Good question. I don't know... 
It's pretty simple in trueRTA.


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