# JL Audio Fathom f113 Ground Plane Results



## Ilkka

Ok, I just got these directly from the JL Audio.  It looks to be a very good performer. 

- 1 meter GP measured from the front baffle (so you need to SUBTRACT 6dB when comparing to 2m GP)
- normal sine waves (i.e. no bursts)


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## bossobass

*Re: Which subwoofers would you like to see tested?*



SteveCallas said:


> I get the feeling this thing is pretty overhyped. :spend:


So much for feelings:
http://www.hometheatershack.com/for...l-audio-fathom-f113-ground-plane-results.html

This sub is pretty much what I've been trying to say for years. Small, stackable, high powered sealed, EQ'd sub done right. That means a great amp and driver with good quality, accurate signal shaping.

No hype, just what's possible to do.

At normal listening levels, this sub (or multiples of it, to meet room size/LP distance requirements) will sound as good as anything available.

I hope to add to the list of possibilities in a separate thread soon, as I believe that I have a bit more experience than JLAudio in this specific arena, but...my jat's off to JL. This F-113 is a great subwoofer, no matter how you slice it.

Great stuff, Ilk:bigsmile: 

Bosso


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## SteveCallas

*Re: Which subwoofers would you like to see tested?*

Ehhh. Better than I was expecting, but it's ~13db down at 20hz and overpriced in my opinion. As KG said a while back, as long as you are slightly handy, there really isn't a good reason not to go DIY. But this isn't the DIY section.


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## bossobass

> Ehhh. Better than I was expecting, but it's ~13db down at 20hz and overpriced in my opinion. As KG said a while back, as long as you are slightly handy, there really isn't a good reason not to go DIY. But this isn't the DIY section


You're always looking only at the maximum output numbers :crying: 

The graph at 104dB, 2M-GP, which is very high output for the small subwoofer buyer, is down 2dB at 20Hz. The higher output graphs show a 12dB/octave slope, as it should be, and the difference is useful for headroom in music transients, also as it should be.

There are also other curve settings available via the E.L.F. trim control on the front panel. (I wish they would have included some sweeps at various positiions of this control in stead of only dupilcating TN's test because it's a significant feature).

The Ref/Variable gain selection is also a great feature.

I also wish they had done some sweeps to verify the LP points/slopes accuracy.

This is simply outstanding performance in it's class...period. I'm here to tell ya, if any DIYer can match this performance in a 1X15" sealed sub, I'd like to shake his/her hand.

Ilk...I've been meaning to ask you: When the compression graphing is done as JL has done it in these graphs, IOW by a series of single-tone points, would there be significance in comparing this to sweeps in that the sweeps should show the difference THD makes between the two methods, or would the THD not influence the upper range of the sweep graph vs the single point graph?

I hope you get to measure this sub, as tests of it's unique features would be very cool info.

Bosso


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## Ilkka

bossobass said:


> This is simply outstanding performance in it's class...period. I'm here to tell ya, if any DIYer can match this performance in a 1X15" sealed sub, I'd like to shake his/her hand.


I agree. It's simply amazing how much performance they've pushed out of a such a small box and by using only a single 13.5" driver. It pretty much matches or slightly surpasses the SVS Plus/2 (20 Hz tune) in 20-40 Hz range, and surpasses it by 3-6 dB anywhere else. 



> Ilk...I've been meaning to ask you: When the compression graphing is done as JL has done it in these graphs, IOW by a series of single-tone points, would there be significance in comparing this to sweeps in that the sweeps should show the difference THD makes between the two methods, or would the THD not influence the upper range of the sweep graph vs the single point graph?


It depends of the subwoofer. Some subs are more tolerant to longer test signals (like 30s sweeps), but some are prone to heat up during them. That of course adds compression and THD. It is a matter of VC and amp cooling how well the sub handles the longer test signals. If I'd had to take a wild guess, I'd say it doesn't really matter how these JL Audio monsters are tested, they will always show similar performance. 



> I hope you get to measure this sub, as tests of it's unique features would be very cool info.
> 
> Bosso


Me too. Too bad that the 230V versions are due late 2007.


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## Sthrndream

>>>It pretty much matches or slightly surpasses the SVS Plus/2 (20 Hz tune) in 20-40 Hz range, and surpasses it by 3-6 dB anywhere else.<<<


If measured the same way as the JL(short term sine wave), I think you'll find the maximum output capabilities of the PB12plus/2 to be much higher than cited in your test posted elsewhere on this site Ilkka. In our tests, the current PB12plus/2(20hz mode) is around 115dB from 40hz and up(2 meter with a 10% thd limit). 20hz is around 104, 25hz is around 110, and 31hz is around 112.

We might be able to have Ed Mullen measure the THD/SPL to see how his data correlates to yours(you both use very similar gear).

Tom V.
SVS


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## Ilkka

Tom Vodhanel said:


> >>>It pretty much matches or slightly surpasses the SVS Plus/2 (20 Hz tune) in 20-40 Hz range, and surpasses it by 3-6 dB anywhere else.<<<
> 
> 
> If measured the same way as the JL(short term sine wave), I think you'll find the maximum output capabilities of the PB12plus/2 to be much higher than cited in your test posted elsewhere on this site Ilkka. In our tests, the current PB12plus/2(20hz mode) is around 115dB from 40hz and up(2 meter with a 10% thd limit). 20hz is around 104, 25hz is around 110, and 31hz is around 112.
> 
> We might be able to have Ed Mullen measure the THD/SPL to see how his data correlates to yours(you both use very similar gear).
> 
> Tom V.
> SVS


Unfortunately I find that very hard to believe Tom. Whether one uses 30s or 5s sines doesn't really matter at the upper end/beginning of the sweep. The output capped at around 107-108 dB @ 100 Hz no matter how hard I pushed it. And at that point the sweep has only ran a couple of seconds. I don't see how you could push it ~7-8 dB higher with any signal. I don't think that for example cooler air could affect that much.

Also users (and one professional review) owning/heard both subs confirm that a single F113 is being stronger/louder than a single Plus/2.

"A single F113 can outgun a single plus/2 on all accounts....but it should be able to....its almost 3 times the cost."

"In my room, the ouput of a single F113 during typical scenes seems to fall in between a single and dual +/2s."

"Personally I owned both the SVS PB 12plus/2 12.3 and the F113 at the same time... I think there was VERY noticable difference between the SVS and JL. A single F113 in my opinion was much more detailed and had more spl than the SVS." 

"As for sound, the JL played deeper, louder, and tighter than the SVS with any material I chose. But this statement doesn’t apply only to the SVS PB12-Plus/2; it applies to every other active sub I’ve heard, at any price."

If your numbers would be correct, how can these people keep reporting the opposite?


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## Sthrndream

Hi Ilkka, That doesn't surprise me...I've found much of your data to be equally “unbelievable”..

Using anecdotal accounts to back up your findings works both ways. What about the axiom ep500/600 owners who claim their subwoofers are better than the plus/2(and other subs that have performed much better in your/avtalk tests) and even provided their own set of “unbelievable” measurements to “prove it”? According to your “unbelievable” measurements…the axiom is one of the worst performing $1500+ subwoofers in history? Obviously this method of trying to verify objective data by quoting selective subjective impressions of new owners isn't reliable. 

Would your point-of-view change if Ed Mullen measured a new Plus/2…or is he also “unbelievable” now?

Tom V.
SVS


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## Ilkka

Tom Vodhanel said:


> Hi Ilkka, That doesn't surprise me...I've found much of your data to be equally “unbelievable”..
> 
> Using anecdotal accounts to back up your findings works both ways. What about the axiom ep500/600 owners who claim their subwoofers are better than the plus/2(and other subs that have performed much better in your/avtalk tests) and even provided their own set of “unbelievable” measurements to “prove it”? According to your “unbelievable” measurements…the axiom is one of the worst performing $1500+ subwoofers in history? Obviously this method of trying to verify objective data by quoting selective subjective impressions of new owners isn't reliable.


Axiom EP-600 was never compared to the Plus/2 but the Ultra instead. And as I recall there was only one user making these claims. And we both know who that was.  And what it comes to their performance differences, they are pretty identical >22 Hz SPL wise. Though Axiom has much higher THD.

I wouldn't compare these comments (especially when one is from a professional review) with the ones said on EP-600 vs. Ultra. Some of them are made by a hardcore SVS fan, so I don't think he would exaggerate the F113's performance. 



> Would your point-of-view change if Ed Mullen measured a new Plus/2…or is he also “unbelievable” now?


It depends what kind of results Ed would present. It doesn't matter who the measurer is, whether the data seems realistic does.


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## bossobass

Ilkka said:


> It depends what kind of results Ed would present. It doesn't matter who the measurer is, whether the data seems realistic does.


Yeah, what's up Ilk? All of a sudden, I have to question all of your test results :R 

I remember the threads where it was suggested by Tom that the SVS subs tested by Europeans were probably faulty, or the testers were in error, and now it seems to be that the slow reverse sine sweep is the culprit?

If Ed tested the F-113 at the same time, it would be interesting, although I honestly believe that Ed's smart enough that he would excuse himself from this sort of situation. It certainly would matter who the measurer is if that measurer is employed by the manufacturer.

No slight against Sir Edward, whom I hold in very high regard, but probably TN would be the guy to measure the Plus/2.

Bosso


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## Ilkka

bossobass said:


> Yeah, what's up Ilk? All of a sudden, I have to question all of your test results :R
> 
> I remember the threads where it was suggested by Tom that the SVS subs tested by Europeans were probably faulty, or the testers were in error, and now it seems to be that the slow reverse sine sweep is the culprit?
> 
> If Ed tested the F-113 at the same time, it would be interesting, although I honestly believe that Ed's smart enough that he would excuse himself from this sort of situation. It certainly would matter who the measurer is if that measurer is employed by the manufacturer.
> 
> No slight against Sir Edward, whom I hold in very high regard, but probably TN would be the guy to measure the Plus/2.
> 
> Bosso


Of course I'm not not 100% comfortable with the JL Audio results either, since they were measured by their own tech, but it seems that the end-user reports and professional reviews correlate well with those results, and not the other way around.

But this doesn't mean that the Plus/2 wouldn't be a good product. It's just that the JL Audio has raised the bar when it comes to packing a tons of output and SQ into a very small box. Naturally it isn't cheap.


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## Guest

There were other things written in the posts that my quotes were taken from but there is no need to add fuel to the fire.

I am enjoying the F113 very much but I DO think that others on some other forums are "overstating" the performance delta bwteen it and other units.

In the few weeks I have had it I can say that my subjective opinion is that in my room it plays lower and louder than a single +/2. I owe nothing to JL and I am still deciding if the sub will stay long term. They have done a great job with this unit.

Another interesting point this has raised in my mind is just how good the +/2 is for the money. You really have to look at the whole picture. There will always be something better out there. How much performance can you offer the consumer for their $$?

[rant]

I am in this for the love of the hobby. I have great respect for SVS, JL, and anyone who is constantly pushing the performance envelope with their products. It is becoming increasingly difficult to post comments without sounding bias for fear of your words being taken out of context. (I am not saying that was done in this post.... but it has been done to me before) I am getting very tired of proofreading everything I say so that I do not contribute to negative sentiment towards a given vendor or put a strain on one of the many friendships I have made in this industry.

[/rant]

-Eli


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## Ilkka

TJEli said:


> There were other things written in the posts that my quotes were taken from but there is no need to add fuel to the fire.


Eli,

I never meant to take your words out of context. I just wanted to show that every user report and professional review I've seen, have said that the F113 is stonger than the Plus/2. And I believe that the objective data has to correlate with those notes. Of course everyone knows that the F113 costs much more than the Plus/2, but this discussion is purely about the performance, not about the price.


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## bossobass

Ilk,

Of course, you're correct, and it goes to my point. I also feel I can't take JL's numbers as Gospel because they themselves ran the test, but...and for the record:

Very early in the F-113 thread I said:



> There's little chance that the Fathom "...played deeper, louder, and tighter than the SVS [SVS PB12-Plus/2] with any material I chose."
> 
> I'd be very surprised if this is true in any sense unless non-linear distortions are not considered. Even then, the Fathom will have a tough time matching output with a 2X12" ported sub from 15-30Hz.
> 
> Above 30Hz, it's possible, but if the subs were level matched in the same system, I doubt it would be easy to catch that one sub played deeper and louder.


So far, the only info we have below 20Hz is Craig's 2M-GP at 16Hz of 93dB as well as his peak hold graph from WOTW that shows higher output below 20Hz.

The sealed sub *should* outperform the ported sub below tune, non-linear distortions notwithstanding, and Craig's info seems to agree with this, and would lend a more powerful edge in presentation to a soundtrack like WOTW, but...

The rest of the BW looks to be fairly equal in any computer model, guessing at T/S from the available info, and is in line with my experience in comparing a 1-2X12" ported vs a higher powered, smaller 1X15" sealed. This info, as I've said elsewhere (long before the F-113 came out), is more in line with what Tom has said here and what I've said in the JL thread.

It looks like either you need to test the F-113 in accordance with the tests you've already done on the Plus/2 or a Plus/2 needs to be tested in accordance with the TN method, as JL's results are taken from...to be fair to Tom, IMHO.

Bosso


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## Guest

I think we should all take a cue from TJEli and relax a little bit.

We certainly find it gratifying and encouraging to have the Fathom compared against some of the best performing subwoofers on the market. I really think the SPL differences between ours and the others mentioned are of little real-world significance to a typical user. The hardcore enthusiast, on the other hand, pays a lot of attention to these numbers as they do illustrate a product's performance envelope and offer a basis for technical comparison, but in the end what matters is how the subwoofer sounds and how it integrates with room aesthetics and available space. Sometimes you have to stop listening to the equipment and simply listen to the music or the movie. I'm pretty sure all of the subs being mentioned can make people happy.

It has been pointed out that some of the competitive products are significantly less expensive than the Fathoms, which is certainly true. But it also important to note (as some have) that they are all significantly larger in size than the Fathom. The f113 has an outside physical envelope, including the grille and feet, of only 3.67 cubic feet (104 liters), whereas the others are all much, much bigger. The SVS PB12-plus/2 is 8.15 cu.ft. (230 liters), the Axiom EP600v2 is 6.7 cu.ft. (190 liters), the Velodyne DD-18 is 5.44 cu.ft. (154 liters). 

If we simply declare their performance levels to be "comparable" or "similar", then the discussion can shift to size/price/cosmetics/features tradeoffs. I think each product, including the Fathom, can make a very good case for itself one way or another. Of course there is room for subjective opinions on performance and personal preferences, but I don't really think there are any "bad choices" in this product grouping... just ones that are based on what the individual values most. Someone choosing a Fathom is likely influenced by the size/performance equation it offers, whereas someone choosing one of the others is more influenced by price/performance, for example. There are customers out there for all of us and we all need to be civil and respectful of each other.

Best regards,

Manville Smith
JL Audio, Inc.


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## Guest

bossobass said:


> It looks like either you need to test the F-113 in accordance with the tests you've already done on the Plus/2 or a Plus/2 needs to be tested in accordance with the TN method, as JL's results are taken from...to be fair to Tom, IMHO.
> 
> Bosso


I need to clarify something. The data that Ilkka has posted is not the measurement series that was done on the f112 to repeat Tom Nousaine's tests.

These are outdoor, 1m GP measurements of an f113, conducted here at JL Audio

The tests took place in our large parking lot early on a Saturday morning (to have a quiet test environment). The calibrated B&K mic was placed on the ground 1 meter from the F113, and levels were measured with our AP. There were no obstructions around the test area for more than 50 feet to be sure the response curves were not perturbed. 

By taking the ground plane tests 1 meter from the subs, we got an output SPL level that was directly comparable to a 1 meter half-space SPL reading without adding any level in post processing. No correction factors were added after taking the actual data. (Therefore, these data are also comparable to a 2 m ground plane test with +6 dB added.) 

The MAX output levels were taken with no monitoring of distortion. We continued to increase the sine wave input until the sub’s output SPL leveled out. We did this via an input voltage sweep with the AP while monitoring output SPL. SPL readings were RMS, not peak. .

Whether you believe them or not is up to you, but let's be clear about the measurement protocol.

Thanks.

Manville Smith
JL Audio, Inc.


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## Guest

Ilkka said:


> Eli,
> 
> I never meant to take your words out of context. I just wanted to show that every user report and professional review I've seen, have said that the F113 is stonger than the Plus/2. And I believe that the objective data has to correlate with those notes. Of course everyone knows that the F113 costs much more than the Plus/2, but this discussion is purely about the performance, not about the price.


No worries Ilkka.

-Eli


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## bobgpsr

msmithJL said:


> ...We continued to increase the sine wave input until the sub’s output SPL leveled out. We did this via an input voltage sweep with the AP while monitoring output SPL...


So I take it, until the onset of compression or actually the end of any more output? It might have been compressing for many dB before the output level no longer changed/increased? This is a bit different than what I have seen before.

It is good that we all are trying to keep our emotions in check and keeping the discussion limited to performance, testing and technical issues.  

Would JL Audio be interested in doing 10% distortion limited tests? That would help IMHO.

Bob


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## Ilkka

bobgpsr said:


> So I take it, until the onset of compression or actually the end of any more output? It might have been compressing for many dB before the output level no longer changed/increased? This is a bit different than what I have seen before.


As the frequency response graph shows, they pushed it as far as it would go, i.e maximum output. 



> Would JL Audio be interested in doing 10% distortion limited tests? That would help IMHO.


How come? One can calculate them already from those results.

20 Hz: 93-94 dB
25 Hz: 99 dB
31.5 Hz: 105 dB


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## Guest

bobgpsr said:


> Would JL Audio be interested in doing 10% distortion limited tests? That would help IMHO.
> 
> Bob


Craigsub has posted 2M GP test results limited to 10%THD.
They are in the thread on AVS.

-Eli


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## Ilkka

TJEli said:


> Craigsub has posted 2M GP test results limited to 10%THD.
> They are in the thread on AVS.
> 
> -Eli


Unfortunately Craig's measurements aren't limited accurately to 10% THD. That's because TrueRTA can not measure THD levels, but one has to manually "eyeball"/calculate them instead.

I checked Craig's screencaps and got the following results.


Code:


	DD18	THD	F113	THD
16 Hz	90.7	10.8	93.8	8.6
20 Hz	95.4	8.2	100.2	9.3
25 Hz	103.1	1.3	109.8	6

Craig's results for the F113 aren't in line with JL's own measurements. They show around 93-94 dB @ 20 Hz and 99 dB @ 25 Hz, both @ 10% THD (2m GP).


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## bobgpsr

Thanks Ilkka. Since that (93 - 94 dB @ 20 Hz) is a 2 pi GP outdoor number, often users would get some room gain for 20 Hz. Personally I would aim for always under 10% THD with goals of 105 dB 20 Hz SPL in room at the Listening Position at a minimum and 115 dB being the ideal. To me at LP getting 115 dB would be a goal for 40 Hz. Right now both of my systems are in rooms that are too big for a single driver sub to do this. Next step for me would be to make a proper home theater in the basement optimized for sound. :daydream: :spend: 

Bob


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## bossobass

msmithJL said:


> I need to clarify something. The data that Ilkka has posted is not the measurement series that was done on the f112 to repeat Tom Nousaine's tests.
> 
> These are outdoor, 1m GP measurements of an f113, conducted here at JL Audio
> 
> The tests took place in our large parking lot early on a Saturday morning (to have a quiet test environment). The calibrated B&K mic was placed on the ground 1 meter from the F113, and levels were measured with our AP. There were no obstructions around the test area for more than 50 feet to be sure the response curves were not perturbed.
> 
> By taking the ground plane tests 1 meter from the subs, we got an output SPL level that was directly comparable to a 1 meter half-space SPL reading without adding any level in post processing. No correction factors were added after taking the actual data. (Therefore, these data are also comparable to a 2 m ground plane test with +6 dB added.)
> 
> The MAX output levels were taken with no monitoring of distortion. We continued to increase the sine wave input until the sub’s output SPL leveled out. We did this via an input voltage sweep with the AP while monitoring output SPL. SPL readings were RMS, not peak. .
> 
> Whether you believe them or not is up to you, but let's be clear about the measurement protocol.
> 
> Thanks.
> 
> Manville Smith
> JL Audio, Inc.


Manville,

I appreciate the detailed response, but I was simply referring to the issue in this thread, that being the differences (or non-differences) between the long reverse sine sweep response graph and the shorter duration single sines at specific frequencies.

TV says the difference using shorter duration single tones is rather dramatic (and more indicative of real-world performance) vs the AVTalk/Ilkka results, when determining maximum output, which opinion Ilk disagrees with.

BTW, we're all pretty relaxed here, but many times a quicker heart rate :heartbeat: leads to greater learning. We're not children who need scolding for engaging in a spirited debate.addle: 

Bosso


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## SteveCallas

Tom said:


> Using anecdotal accounts to back up your findings works both ways. What about the axiom ep500/600 owners who claim their subwoofers are better than the plus/2(and other subs that have performed much better in your/avtalk tests) and even provided their own set of “unbelievable” measurements to “prove it”? According to your “unbelievable” measurements…the axiom is one of the worst performing $1500+ subwoofers in history?


:heehee: I still love thinking about this one. Yeah, the 600 measures astoundingly horrible, both in time/energy response and third order harmonic distortion that far eclipses the H2 over a nice chunk of frequencies. Goes to show, you always have to consider the person making the comments. 

msmsithJL - how about you send Ilkka a sub for testing? :yes:


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## bossobass

It certainly would depend on the system the sub's in, how far away you're sitting and at what levels you are listening to what source material.

As Ilk pointed out, the comparison's mentioned are not with the Plus/2 and at certain levels, the 2 would not be that different.

The real point of this thread is in the title: The GP measurements of the F-113. TV pointed out that the short duration single tone test does not correlate closely to the slower reverse sine sweep done on the Plus/2.

Ilk disagrees.

This is a great point for discussion, IMO, because all of the respected reviewers whose results appear on the internet use one of these two max output, or THD limited output methods.

Bosso


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## SteveCallas

It should be easy enough to resolve. If the snow has melted, Ilkka can measure one of his subs for max output using both methods.


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## Ilkka

SteveCallas said:


> :heehee: I still love thinking about this one. Yeah, the 600 measures astoundingly horrible, both in time/energy response and third order harmonic distortion that far eclipses the H2 over a nice chunk of frequencies. Goes to show, you always have to consider the person making the comments.


Since I have listened the EP-600 also in my room, I wouldn't call it horrible. Yes, most of the measurements don't look good, but the most important ones aren't that bad. It has a pretty good frequency response, not the greatest extension but still adequate. Maximum output in the most important range is good, although anywhere else only moderate. Even though the THD is high at all levels, it consists mainly out of 2nd and 3rd harmonics. So subjectively it doesn't sound that bad. Many other subs that I have tested have sounded subjectively much worse, even though the absolute THD levels have been lower. IMO that is one of the key features of the EP-600 (and EP-500 too), it behaves extremely well even when pushed "way too far". It reminds me of the Velo's servo control. It isn't the deal of the century, but it isn't the worst sub either. 



> msmsithJL - how about you send Ilkka a sub for testing? :yes:


Unfortunately the 230V versions are due late 2007.


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## Ilkka

bossobass said:


> The real point of this thread is in the title: The GP measurements of the F-113. TV pointed out that the short duration single tone test does not correlate closely to the slower reverse sine sweep done on the Plus/2.
> 
> Ilk disagrees.
> 
> This is a great point for discussion, IMO, because all of the respected reviewers whose results appear on the internet use one of these two max output, or THD limited output methods.
> 
> Bosso


Bosso, (or should I call you Bo?  )

I disagree because my own measurements have shown that there is virtually no difference. Here's a quick table I made. Since I took the both readings in my first shootout, it is really easy to compare them. Max SPL means the maximum SPL during the long reversed sine sweep, and the <10% THD means the maximum SPL at less than 10% THD using 2-5s sine waves (i.e. no sweep).

You can see that both methods give very similar results. Obviously THD limited output is lower at the points where the THD went over the 10% limit. But the maximum output taken with the single sine waves doesn't deviate more than 1-2 dB from the max output taken with the sweep. At the bottom of the table you can see the calculated averages (20 Hz value is being left out for obvious reasons). The maximum deviation is 0.9 dB, while the average deviation is 0.44 dB. That isn't a large enough difference for me to abandon the sweep method, especially when it has some obvious advantages over the single sines.

You can also check Ed Mullen's measurements, and you'll notice the very similar trend.


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## Ilkka

SteveCallas said:


> It should be easy enough to resolve. If the snow has melted, Ilkka can measure one of his subs for max output using both methods.


No need to wait, those measurements have already been taken. Check above...


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## bossobass

Ilkka said:


> Bosso, (or should I call you Bo?  )


Now, THAT was funny:jump: 

I apologize, Ilkka. My propensity to shorten names to a single syllable has obviously offended in this case.

Noted.

Bosso


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## Ilkka

bossobass said:


> Now, THAT was funny:jump:
> 
> I apologize, Ilkka. My propensity to shorten names to a single syllable has obviously offended in this case.
> 
> Noted.
> 
> Bosso


Definitely not offended. It just looks funny. :R


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## SteveCallas

Ilkka said:


> You can see that both methods give very similar results. Obviously THD limited output is lower at the points where the THD went over the 10% limit


Well I think this is key, no? JL's max output figures aren't 10% THD limited and Tom made no mention of 10% THD limited max output. 



Tom said:


> If measured the same way as the JL(short term sine wave), I think you'll find the maximum output capabilities of the PB12plus/2 to be much higher than cited in your test posted elsewhere on this site Ilkka


You would have to compare max output from a long sweep to max output from a sine wave, disregarding THD, cause that's what JL did. I'd bet you'd see a pretty significant difference, cause if we use JL's numbers as an example, they are getting 117.1db at 31.5hz as max output from 1m, yet in the THD measurements from 1m, 115db at 31.5hz is already causing ~19.5% THD. Seeing as the difference between 110db levels and 115db levels caused a ~10% THD increase at 31.5hz, one would have to figure that in order to achieve the 117.1db figure, THD was over 30%.


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## bossobass

SteveCallas said:


> Well I think this is key, no? JL's max output figures aren't 10% THD limited and Tom made no mention of 10% THD limited max output.
> 
> 
> You would have to compare max output from a long sweep to max output from a sine wave, disregarding THD, cause that's what JL did. I'd bet you'd see a pretty significant difference, cause if we use JL's numbers as an example, they are getting 117.1db at 31.5hz as max output from 1m, yet in the THD measurements from 1m, 115db at 31.5hz is already causing ~19.5% THD. Seeing as the difference between 110db levels and 115db levels caused a ~10% THD increase at 31.5hz, one would have to figure that in order to achieve the 117.1db figure, THD was over 30%.


Exactly my point.

Very important stuff, here. Question is, can subs be compared without a disclaimer when the two methods are used? Pretty big question, IMO.

And, where do Siegfried's shaped tone bursts fit in (ala Yates' WDD)?

Bosso


----------



## SteveCallas

> Question is, can subs be compared without a disclaimer when the two methods are used?


When one sub is measured for raw max output and the other is measured for 10% THD limited max output, I don't think any legitimate comparisns can be made. As such, I still see Tom's point as being valid. 

Is raw max output really important though? Do you want lots of distortion with your sub? When amp limiting something like a LLT, I'd bet that max raw output wouldn't be any higher than 10% THD limited output from ~30hz on up.


----------



## bossobass

If you look at Yates' stuff, the differences between max output using a slow sine sweep or the short tone burst at 'just shy of audible distortion', it seems to be very subwoofer dependent as to how those numbers correlate to the slow sine sweep max output results, which record THD but don't limit output by it.

Most of the better subs show the sort of difference Tom alluded to from the short burst tests to the slow sine sweep tests.

So, if, for example, you looked at Yates' short burst test results of a given sub against Ilkka's reverse sweep tests of a different sub, the Yates tested sub may show 6dB or more output at certain frequencies than it would looking at Yates' sine sweep results, even though Yates' test short burst test limits distortion (by ear).

As far as the LLT's performance in either of these tests goes, if you amp limit, which I think means protect the driver by having less power available than the sub could normally use if protected by a HP, max output would be limited by the amplifier, which would clip and/or compress at the top of the amp's limits. And, the LLT would still bottom below tune during the sine sweep compression test or the short burst test before the amp's limit, unless the amp's HP filter happened to be at the LLT's tune.

So, even though it would limit THD, it's the same difference to not running the next higher level sweep of a sub that's not amp limited.

Bosso


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## Ilkka

Guys, you are mixing up some things. :nono: Let's go over what was said...

1. I said the F113 would match or slightly surpass the Plus/2 in maximum output in 20-40 Hz range and surpass it by 3-6 dB everywhere else. This analysis was based on comparing JL's own data to my data on the Plus/2 measured with the sweep method. So no THD limiting was done in either case.

2. Then Tom V chimes in and says that his own data measured with single sines and using 10% THD limit shows much higher output for the Plus/2 than what my sweep method shows. So he's suggesting that the sweep method produces clearly lower max output levels. Clearly being over 6 dB in the higher end of the test spectrum.

3. I reply that I haven't notice the same phenomenan in my testing. Do notice that I did use both methods in my first two measuring sessions. If there is that large difference between out data, it is caused by some other things, not by different test signals. I also point out that the end-user reports and professional reviews do correlate better with my data. 10 out of 10 end-users report back the F113 being stronger/louder/"deeper" than the Plus/2. I point out that it is also much more expensive so I'm not accused of not telling that.

4. Then bobgpsr brings up the 10% THD limited output for the F113, and I derivate the numbers for him from the data JL Audio has provided. As you can see, even at 115 dB level (@1m) the THD stays under 10% until 31.5 Hz. That means I can calculate the 10% THD limited output only at 20 Hz, 25 Hz and 31.5 Hz. And the numbers are: 93-94 dB @ 20 Hz, 99 dB @ 25 Hz and 105 dB @ 31.5 Hz.

5. Then Bosso asks again why I disagree with Tom's opinion that the sweep method produces much lower maximum output levels. I reply by showing a table where I have gathered maximum SPLs obtained with both sweep and single sine wave methods. The fact that the single sine wave numbers are limited by the 10% THD limit doesn't make a large difference in the group of the subwoofers being tested. That's because some subwoofers, especially large commercial ported ones, won't allow >10% THD levels until at very low frequencies/below the tuning frequency due amp limiters (and this is not the same "amp limiting" what SteveC means) and the nature of the desing. Of course this doesn't apply to all commercial ported subs, some may have more loose limiters or just simply have very high THD levels by desing. Most of the (all?) DIY subs don't have any amp limiters at all.

Here are more thorough THD/output analysis for the SVS 20-39PC+ and the SVS PB12-Ultra.



Code:


[b]SVS 20-39PC+ 20 Hz (dB12.2)[/b]		

Freq. (Hz) SPL (dB) THD (%)

20	97.9	10.6
25	104.5	3.5
32	107.7	6.1
40	107.9	6.6
50	106.5	5.9
63	104.6	5.2
80	103.2	4.1

[b]SVS PB12-Ultra 20 Hz[/b] 		

Freq. (Hz) SPL (dB) THD (%)

20	102.6	9.8
25	105.9	4.2
32	109.1	8
40	109	8.7
50	106	4.7
63	103.4	3.1
80	101.6	1.9

As you can see, I couldn't get the THD to go near/above 10% until at 20 Hz, which is already slightly below the true, measured tuning frequency for both subwoofers. That of course means that BOTH maximum output and 10% THD limited output are THE SAME at all test frequencies except 20 Hz. Of course that doesn't apply to all subwoofers, only to ones with low overall THD levels. Not a single sealed subwoofer qualifies here due the nature of the THD profile of the sealed alignment. Since the output is produced solely by the woofer, the THD grows quite linearly (actually more like logarithmically) towards the lower frequencies. That means that the 10% THD limited SPL isn't the maximum output for sealed subwoofers at low frequencies. The transition frequency depends of the output capabilities of the subwoofer (and motor technology), but for example for the F113 is seems to be somewhere in 30-40 Hz range. Of course this shouldn't come as a surprise to anyone with more than basic knowledge of different subwoofer alignments.

SteveC asked whether raw maximum output or THD limited output is more important. I'd say the key thing is to keep the audible distortion low. As we know, the absolute amount of THD doesn't tell us much. 20-30% of mainly 2nd and 3rd order HD at low frequencies isn't that bad. I would challenge anyone to spot it during program material. And don't forget the discussion we had over at TC-Sounds forum, sometimes higher THD is perceived as there was more punch and kick, as Bosso's experiments showed us. What we measure is one thing and what we hear is another. 

I'll try to quickly wrap up this all. Based on my own and Ed Mullen's measurements, I do believe sweep and single sine wave methods produce almost identical results (within 0-2 dB) when it comes to maximum output. The 10% THD limited max output using single sine waves produces identical results with the methods mentioned earlier, in the case where the amp limiter/desing won't allow >10% THD levels. I don't personally support the 10% THD limit anymore because it doesn't really tell much about the audibility of the THD. It doesn't also tell what happens at the levels lower than 10% THD. The sweep method can end up with slightly higher THD levels due VC heating, especially at the low end of the spectrum (or below the real tuning frequency), and with subwoofers having low tolerance for VC heating, i.e. bad VC cooling. I don't see it being a large problem over the other advantages it has.


----------



## Ilkka

bossobass said:


> If you look at Yates' stuff, the differences between max output using a slow sine sweep or the short tone burst at 'just shy of audible distortion', it seems to be very subwoofer dependent as to how those numbers correlate to the slow sine sweep max output results, which record THD but don't limit output by it.
> 
> Most of the better subs show the sort of difference Tom alluded to from the short burst tests to the slow sine sweep tests.
> 
> So, if, for example, you looked at Yates' short burst test results of a given sub against Ilkka's reverse sweep tests of a different sub, the Yates tested sub may show 6dB or more output at certain frequencies than it would looking at Yates' sine sweep results, even though Yates' test short burst test limits distortion (by ear).
> 
> As far as the LLT's performance in either of these tests goes, if you amp limit, which I think means protect the driver by having less power available than the sub could normally use if protected by a HP, max output would be limited by the amplifier, which would clip and/or compress at the top of the amp's limits. And, the LLT would still bottom below tune during the sine sweep compression test or the short burst test before the amp's limit, unless the amp's HP filter happened to be at the LLT's tune.
> 
> So, even though it would limit THD, it's the same difference to not running the next higher level sweep of a sub that's not amp limited.
> 
> Bosso


Bosso,

Please don't confuse Yates' (Linkwitz's) "tone bursts" with the "short term sine waves" mentioned by Tom V. Tom still means regular, couple of seconds long sine waves, not 250ms or less 1/3 oct. wide tone bursts. Those are a whole different matter and weren't meant by either me or Tom.

But you are being correct that by using those very short (for example 5 cycle) tone bursts, it is possible to gain as much as 6 dB over the sweep or regular single sine waves, depending of the subwoofer and frequency of course. In most cases it is possible because the short tone doesn't trigger the amp limiter, but obviously some of it is also due lesser VC heating. Whether this or the sweep/single sine method correlates better with real program material is being debated.


----------



## SteveCallas

> As you can see, I couldn't get the THD to go above 10% until at 20 Hz, which is already slightly below the true, measured tuning frequency for both subwoofers. That of course means that BOTH maximum output and 10% THD limited output are THE SAME at all test frequencies except 20 Hz. Of course that doesn't apply to all subwoofers, only to ones with low overall THD levels. Not a single sealed subwoofer qualifies here due the nature of the THD profile of the sealed alignment.


Ok, I gotcha now, the Plus/2 is incapable of producing output with more than 10% THD from anywhere above tuning. Sorry for creating any confusion :doh:


----------



## Ilkka

SteveCallas said:


> Ok, I gotcha now, the Plus/2 is incapable of producing output with more than 10% THD from anywhere above tuning. Sorry for creating any confusion :doh:


Yes, although naturally there can be small variances/exceptions due ambient temperature, sweep/tone lenght etc.

But as the measurement below shows, above the tuning frequency the THD goes over 10% only around 40 Hz, and even then only by 1-3%. Anywhere else it's impossible to push it above 10%.

And do notice that the tuning frequency shifts up when the air velocity in the port(s) goes up. Even though the measured (low-level) tuning frequency is around 25.2 Hz, at high port velocities it's more closer to 28 Hz (THD minimum).


----------



## bossobass

This is where my confusion comes from:



> 2. Then Tom V chimes in and says that his own data measured with single sines and using 10% THD limit shows much higher output for the Plus/2 than what my sweep method shows. So he's suggesting that the sweep method produces clearly lower max output levels. Clearly being over 6 dB in the higher end of the test spectrum.


Tom Chiming in:



> If measured the same way as the JL(short term sine wave), I think you'll find the maximum output capabilities of the PB12plus/2 to be much higher than cited in your test posted elsewhere on this site Ilkka.


I don't see where Tom mentions a 10% THD limit. I think he clearly meant max output measured with shorter single tone signal (like JL's test, since those numbers are being compared to your numbers for the Plus/2) vs a long reverse sine sweep.

Bosso


----------



## Ilkka

bossobass said:


> This is where my confusion comes from:
> 
> I don't see where Tom mentions a 10% THD limit. I think he clearly meant max output measured with shorter single tone signal (like JL's test, since those numbers are being compared to your numbers for the Plus/2) vs a long reverse sine sweep.
> 
> Bosso


Here's the full quote from Tom.



Tom V said:


> If measured the same way as the JL(short term sine wave), I think you'll find the maximum output capabilities of the PB12plus/2 to be much higher than cited in your test posted elsewhere on this site Ilkka. In our tests, the current PB12plus/2(20hz mode) is around 115dB from 40hz and up(*2 meter with a 10% thd limit*). 20hz is around 104, 25hz is around 110, and 31hz is around 112.


So those numbers are 10% THD limited. And as I have tried to explain, it really doesn't matter whether one looks at the 10% THD or maximum output numbers for the Plus/2 - they are pretty much identical above the tuning frequency.


----------



## Ed Mullen

In my last professional review for Secrets (Klipsch RT-12d), I switched over to the CEA 2010 standard for distortion audibility in subwoofers.

Note here under the "Harmonic Distortion" section the summary table showing the pertinant data, and the accompanying screen shots.

http://www.hometheaterhifi.com/volume_13_4/klipsch-rt-12d-subwoofer-december-2006-part-2.html

I think this format and the CEA 2010 standard should be adopted to determine maximum "audibly clean" output at any discrete frequency. 

While Ilkka does measure (and weight) the amplitude of distortion harmonic orders 2-6, the sound pressure level at which the data is collected is arbitrary and varies with each subwoofer. We cannot tell from his data whether or not the subwoofer is failing or passing the CEA 2010 standard - all we know is the relative relationship of the distortion harmonics (with a weighting metric applied) at an arbitrary sound pressure level (defined below).



Ilkka said:


> The chosen sweep level wasn’t kept the same for all subs because of different max output levels. Usually the second highest sweep was chosen. That’s why you shouldn’t compare the absolute levels between different subwoofers, only relative levels between harmonics.


The issue I have with the above method is that the relative relationship of the distortion harmonics can/will vary with amplitude. And therefore these changes can/will affect the CEA 2010 output limits. I noticed this phenomenon most obviously when testing the Canton 850SC. Above a certain sound pressure level, the 3rd order distortion harmonic would suddenly jump to a much higher level - and the sound quality obviously changed at that point. Ilkka's method would not necessarily have caught the onset of this change in the spectral behavior of the subwoofer - he might have been above or below the break point.



Ilkka said:


> The individual levels for harmonics from second (H2) to sixth (H6) were manually plotted at 20 Hz, 25 Hz, 32 Hz, 40 Hz, 50 Hz, 63 Hz and 80 Hz. H6 was chosen as the highest harmonic, because very few subs had any THD above that.


Some of my recent testing contradicts this blanket statement. Note in the Klipsch RT-12d review, the CEA 2010 output limit was capped by the 10th order harmonic at 20 Hz, the 9th order harmonic at 32 Hz, and the 12th/13th order harmonic at 40 Hz. These higher order harmonics are more audible/objectionable than the lower order harmonics, and accordingly have been assigned much lower capping thresholds by the 2010 standard.

As for the differences in sound pressure levels measured by Ilkka and SVS R&D, the only way to settle that would be to get both test rigs together in the same location and measure the same subwoofer at the same time. Until that point, we can only speculate as to why there are differences in absolute SPL.

Similarly, the only way to determine the relative differences between the F113's and the Plus/2's "audibly clean" output limits (CEA 2010) and the maximum output limits (i.e., without regard for distortion levels) would be to test them side-by-side under the same conditions with the same test rig using the same methodology.


----------



## Ilkka

Ed Mullen said:


> In my last professional review for Secrets (Klipsch RT-12d), I switched over to the CEA 2010 standard for distortion audibility in subwoofers.
> 
> Note here under the "Harmonic Distortion" section the summary table showing the pertinant data, and the accompanying screen shots.
> 
> http://www.hometheaterhifi.com/volume_13_4/klipsch-rt-12d-subwoofer-december-2006-part-2.html
> 
> I think this format and the CEA 2010 standard should be adopted to determine maximum "audibly clean" output at any discrete frequency.


Hi Ed,

Technically your testing wasn't exactly according to the CEA 2010 standard. You used standard sine waves while CEA 2010 uses 6.5 cycle long (hann weighted) ~1/3 octave wide tone bursts, similar to what Keith Yates used in his WDD review. As Bosso noted, by using these bursts, Yates was able to pull out as much as 6 dB higher max output levels (before audible distortion) as with continuous sine waves. Therefore I wouldn't compare the results taken with your method to the results taken with the official CEA 2010 method. 



> While Ilkka does measure (and weight) the amplitude of distortion harmonic orders 2-6, the sound pressure level at which the data is collected is arbitrary and varies with each subwoofer. We cannot tell from his data whether or not the subwoofer is failing or passing the CEA 2010 standard - all we know is the relative relationship of the distortion harmonics (with a weighting metric applied) at an arbitrary sound pressure level (defined below).
> 
> The issue I have with the above method is that the relative relationship of the distortion harmonics can/will vary with amplitude. And therefore these changes can/will affect the CEA 2010 output limits. I noticed this phenomenon most obviously when testing the Canton 850SC. Above a certain sound pressure level, the 3rd order distortion harmonic would suddenly jump to a much higher level - and the sound quality obviously changed at that point. Ilkka's method would not necessarily have caught the onset of this change in the spectral behavior of the subwoofer - he might have been above or below the break point.
> 
> Some of my recent testing contradicts this blanket statement. Note in the Klipsch RT-12d review, the CEA 2010 output limit was capped by the 10th order harmonic at 20 Hz, the 9th order harmonic at 32 Hz, and the 12th/13th order harmonic at 40 Hz. These higher order harmonics are more audible/objectionable than the lower order harmonics, and accordingly have been assigned much lower capping thresholds by the 2010 standard.


I've never claimed that my method would try to replicate the CEA 2010 standard. I just wanted to show the harmonic breakdown (weighted according to the CEA 2010) at near max output levels (that's why the second highest sweep was chosen). It doesn't show where the THD exceeds the CEA 2010 limit or becomes audible. Although when comparing my subjective notes taken during the tests to the results, they compare really well. Subwoofers having mainly 2nd and 3rd order HD didn't sound that bad even though the absolute THD was relatively high (especially at lower frequencies). At the same time subwoofers having lots of 5th and 6th order (and higher) HD sounded much worse. I decided to show the harmonics H2-H6 because most of the subwoofers being tested didn't have high levels of HD above that (naturally some did), and partly because the plotting was done manually (lots of work even with five harmonics). You just can not take or show all the data you would like to when you're dealing with 20 something subwoofers. :yikes: 

BTW, why criticize my testing methods in this thread when there's a dedicated forum and threads where to discuss about these things? I don't also quite see how this all relates to the topic? 



> As for the differences in sound pressure levels measured by Ilkka and SVS R&D, the only way to settle that would be to get both test rigs together in the same location and measure the same subwoofer at the same time. Until that point, we can only speculate as to why there are differences in absolute SPL.
> 
> Similarly, the only way to determine the relative differences between the F113's and the Plus/2's "audibly clean" output limits (CEA 2010) and the maximum output limits (i.e., without regard for distortion levels) would be to test them side-by-side under the same conditions with the same test rig using the same methodology.


Agree. It's a shame that you can not do that kind of testing anymore. :no:


----------



## SteveCallas

Ed said:


> While Ilkka does measure (and weight) the amplitude of distortion harmonic orders 2-6, the sound pressure level at which the data is collected is arbitrary and varies with each subwoofer. We cannot tell from his data whether or not the subwoofer is failing or passing the CEA 2010 standard - all we know is the relative relationship of the distortion harmonics (with a weighting metric applied) at an arbitrary sound pressure level (defined below).


I prefer Ilkka's method of measuring THD, as it gives me a direct visual representation of how it changes by frequency at various levels as opposed to say a chart of numbers. It's more in the vein of Edward Tufte, who's philosophy was stressed to me time and again in college (which I happen to agree with).


----------



## Ed Mullen

Ilkka said:


> Hi Ed,
> 
> Technically your testing wasn't exactly according to the CEA 2010 standard. You used standard sine waves while CEA 2010 uses 6.5 cycle long (hann weighted) ~1/3 octave wide tone bursts, similar to what Keith Yates used in his WDD review. As Bosso noted, by using these bursts, Yates was able to pull out as much as 6 dB higher max output levels (before audible distortion) as with continuous sine waves. Therefore I wouldn't compare the results taken with your method to the results taken with the official CEA 2010 method.


Yes, that is correct and everyone can tell by looking at the spectral screen shots that I was using straight sines - in fact I was the first to acknowledge months ago at AVS that no one would strictly comply with the 2010 standard unless they used Keele's tone bursts. 

The idea here (and what I'm advocating) is to move beyond using a strict and arbitrary distortion-limited output value and recognize the value of the spirit of the CEA 2010 standard - and that is the relative audibility of progressively higher distortion harmonics. And if straight sines are used for every subwoofer, that method is then eliminated as a test variable.

The key point here is _not_ the maximum output differential between a 6.5 cycle tone burst and a straight short term (3-4 seconds) sine; we all know most subwoofers can generate a higher SPL with a tone burst - but they also generate higher distortion levels at the same time. 

The key question here is: Does measuring distortion-limited SPL with a 6.5 cycle tone burst provide a significantly different result than when measuring distortion-limited SPL with a short term straight sine wave? 

We would have to test a subwoofer with both methods to determine this - but would you care to venture an educated guess? My gut tells me the two methods will generate very similar distortion-limited SPL results. In other words, would it make much sense if a given subwoofer generated something like 102 dB @ 20 Hz @ 10% THD with a 6.5 cycle tone burst, and then generated 96 dB @ 20 Hz @ 10% THD with a 2-3 second sine wave? 



Ilkka said:


> I've never claimed that my method would try to replicate the CEA 2010 standard. I just wanted to show the harmonic breakdown (weighted according to the CEA 2010) at near max output levels (that's why the second highest sweep was chosen). It doesn't show where the THD exceeds the CEA 2010 limit or becomes audible. Although when comparing my subjective notes taken during the tests to the results, they compare really well. Subwoofers having mainly 2nd and 3rd order HD didn't sound that bad even though the absolute THD was relatively high (especially at lower frequencies). At the same time subwoofers having lots of 5th and 6th order (and higher) HD sounded much worse. I decided to show the harmonics H2-H6 because most of the subwoofers being tested didn't have high levels of HD above that (naturally some did), and partly because the plotting was done manually (lots of work even with five harmonics). You just can not take or show all the data you would like to when you're dealing with 20 something subwoofers. :yikes:


I never stated you were claiming otherwise. I know exactly what you are trying to accomplish with this method of data presentation, and I think it has a lot of merit because it recognizes the relative audibility of progressively higher distortion harmonics. 

But if you are going to use this method as a tool to compare subwoofers, then the next logical step is to gravitate to something like the CEA 2010 limits to compare the maximum "audibly clean" output limits at discrete frequencies using the same distortion harmonic caps for every subwoofer - it levels the playing field in much the same manner as we previously did with the 10% THD SPL limits. The CEA 2010 method is simply more refined and (per your own observations) will provide a better correlation with what we subjectively perceive. 

The value of a huge database not withstanding, it would not take long to apply a -12 dB/octave limiting line (-40 dB horizontal above 10th order) to a screen shot and find the approximate CEA 2010 output limit under field testing. In fact it would probably take less time than your current method and would ultimately provide more useful data from a comparison standpoint. 



Ilkka said:


> BTW, why criticize my testing methods in this thread when there's a dedicated forum and threads where to discuss about these things? I don't also quite see how this all relates to the topic?


You were the first person in this thread to state the F113 has higher output capability than the Plus/2 and you cited your own data sources to prove it. And TV refuted that, stating that JL used short sines, and you used a 30 second sweep, and this could be the difference between the two data sets, and that SVS R&D measured significantly different results that you did. 

You then cited several examples using your own data to support your position. At that point the thread largely derailed into a discussion of various test methods, centering around the differences between tone bursts, short sines, 30 second sine sweeps, distortion-limited output, and maximum output without regard to distortion. 

At that point a discussion of your test data becomes relevant, because you introduced it into the thread at several points. I am merely citing my opinion on which direction we should collectively (as a testing community) take regarding subwoofer output measurements. You and AVTalk are a big part of that community and we want you to test our subwoofers in the future. So instead of viewing it as a criticism of your current methodology, view it as open dialogue about the possibility everyone gravitating to a test method which complies with the _spirit_ of the 2010 standard (even if it uses short sines). 

Your discussion section on distortion audibility clearly recognizes the value of the 2010 standard because you used it as the weighting metric. The CEA 2010 standard is a natural evolution of the 10% THD limited output pioneered by TN years ago, and I encourage you to consider adopting it as your new standard for measuring audibly clean output from all subwoofers tested. 



Ilkka said:


> Agree. It's a shame that you can not do that kind of testing anymore. :no:


I'll be doing plenty of testing of both our subwoofers and the competition. I just won't be publicly publishing the data. I'll be using the CEA 2010 standard to determine maximum clean output limits at discrete frequencies, and I hope you'll consider doing the same. We've partnered together on many subwoofer testing/measurement projects over the years and I have nothing but respect for your abilities. I see no reason why we (along with AVTalk) can't continue working together in the future to further advance the state of the art of subwoofer testing/measuring.


----------



## bobgpsr

^^^ Bravo for the call to working together Ed. I must have missed it. When did you start working for SVS? Impressive that they managed to get such a respected subwoofer testing personage. :clap: 

I will miss your test numbers of the competition though. :dontknow:


----------



## bossobass

If there was a dB or 2 difference here, I could swallow the different rigs angle, but, as Ilkka has said...7-8dB difference with a 10% THD cap needs to have some sort of logical explanation.

So far (not that all of the other technical info isn't useful and appreciated), we have TV's thought that it's simply the duration of the tones.

I personally think that Ilkka has explained that one away by looking at the top end of the reverse sine sweep.

Anything to add, Ed?

Bosso


----------



## Ed Mullen

bossobass said:


> If there was a dB or 2 difference here, I could swallow the different rigs angle, but, as Ilkka has said...7-8dB difference with a 10% THD cap needs to have some sort of logical explanation.
> 
> So far (not that all of the other technical info isn't useful and appreciated), we have TV's thought that it's simply the duration of the tones.
> 
> I personally think that Ilkka has explained that one away by looking at the top end of the reverse sine sweep.
> 
> Anything to add, Ed?
> 
> Bosso


Yeah 0-2 dB is within normal variations between test rigs. But 5-7 dB? Nope - something is wrong. Like I said above, the only way to tell what is happening is to get both test rigs at the same location and calibrate them and take some measurements on the same subwoofer. Software glitch, flaky absolute SPL calibration, processor limitations - who knows. 

I know getting Ilkka's test rig to the states or SVS' to Finland is out of the question, that's why TV suggested I measure a Plus/2 because Ilkka and I have similar test rigs. 

FWIW, here's what I measured from the PB12-Plus with the 12.2 woofer. Above about 40 Hz, add 6 dB to each value and you should be pretty close to a Plus/2 with 12.2 woofers. Below 40 Hz and the gap starts to close since the Plus/2 is more port limited in the 20 Hz tune than the Plus.

The 12.3 woofer has a bit more (1-2 dB) midrange output capability than the 12.2, so you might want to add ~7.5 dB to each value for the 12.3. Again, it's bench racing but it might help as a comparative tool. 

Frequency (Hz) / 20 Hz Tune SPL (dB) / 20 Hz Tune THD (%)

18	91.1	10.2
20	101.3	10.4
22	104.0	3.7*
25	105.8 6.4*
32	108.4	8.5*
40	108.5	4.5*
50	107.2	3.8*
63	106.0	3.6*
80	104.2	4.0*

* output was capped by the amplifier limiter before THD reached 10%


----------



## Ilkka

Ed Mullen said:


> Yes, that is correct and everyone can tell by looking at the spectral screen shots that I was using straight sines - in fact I was the first to acknowledge months ago at AVS that no one would strictly comply with the 2010 standard unless they used Keele's tone bursts.


Ok, I remember this. Although I would have liked to see it mentioned in your review too, next to the CEA 2010 scores you listed for the Klipsch. 



> The idea here (and what I'm advocating) is to move beyond using a strict and arbitrary distortion-limited output value and recognize the value of the spirit of the CEA 2010 standard - and that is the relative audibility of progressively higher distortion harmonics. And if straight sines are used for every subwoofer, that method is then eliminated as a test variable.
> 
> The key point here is _not_ the maximum output differential between a 6.5 cycle tone burst and a straight short term (3-4 seconds) sine; we all know most subwoofers can generate a higher SPL with a tone burst - but they also generate higher distortion levels at the same time.
> 
> The key question here is: Does measuring distortion-limited SPL with a 6.5 cycle tone burst provide a significantly different result than when measuring distortion-limited SPL with a short term straight sine wave?
> 
> We would have to test a subwoofer with both methods to determine this - but would you care to venture an educated guess? My gut tells me the two methods will generate very similar distortion-limited SPL results. In other words, would it make much sense if a given subwoofer generated something like 102 dB @ 20 Hz @ 10% THD with a 6.5 cycle tone burst, and then generated 96 dB @ 20 Hz @ 10% THD with a 2-3 second sine wave?


AFAIK only Keith Yates has done any serious comparison between bursts and normal sine waves. Although even his data can not clearly answer to your question. But if some subs (Velodyne DD18 for example) pull out 6-7 dB higher max output levels (before audible distortion) with bursts than with straight sines, I don't think it matters whether the absolute amounts of distortion are identical or not. If those subs can not even get up to those levels with straight sines, it doesn't matter whether they generate more or less THD with burst tones. Sure if everyone would use straight sines, I guess it would be a fair play, although since there IS a CEA 2010 standard, shouldn't we follow it exactly, instead of creating our own little standard? I'm pretty sure at some point someone would be questioning whether I used 2s or 5s sines, and what kind of difference that would make. When using 6.5 cycle long bursts, there's no room for that. 



> The value of a huge database not withstanding, it would not take long to apply a -12 dB/octave limiting line (-40 dB horizontal above 10th order) to a screen shot and find the approximate CEA 2010 output limit under field testing. In fact it would probably take less time than your current method and would ultimately provide more useful data from a comparison standpoint.


It would definitely take more time. 7-8 new measurements per sub to be more exact. We both know what Spectra Pro is missing, and without it, it's going to take lots of manual work to be able to solve those limits. Believe me, if there would be an easy and fast way, I'd have used it already. 



> Your discussion section on distortion audibility clearly recognizes the value of the 2010 standard because you used it as the weighting metric. The CEA 2010 standard is a natural evolution of the 10% THD limited output pioneered by TN years ago, and I encourage you to consider adopting it as your new standard for measuring audibly clean output from all subwoofers tested.


What makes you think that I haven't considered it (or gone even further)?  



> I'll be doing plenty of testing of both our subwoofers and the competition. I just won't be publicly publishing the data. I'll be using the CEA 2010 standard to determine maximum clean output limits at discrete frequencies, and I hope you'll consider doing the same. We've partnered together on many subwoofer testing/measurement projects over the years and I have nothing but respect for your abilities. I see no reason why we (along with AVTalk) can't continue working together in the future to further advance the state of the art of subwoofer testing/measuring.


Agree. Although you must understand that there are some differences whether one is measuring two or twelve subwoofers in a day. More data -> less subwoofers...


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## Ilkka

bossobass said:


> If there was a dB or 2 difference here, I could swallow the different rigs angle, but, as Ilkka has said...7-8dB difference with a 10% THD cap needs to have some sort of logical explanation.
> 
> So far (not that all of the other technical info isn't useful and appreciated), we have TV's thought that it's simply the duration of the tones.
> 
> I personally think that Ilkka has explained that one away by looking at the top end of the reverse sine sweep.
> 
> Anything to add, Ed?
> 
> Bosso


When looking at the differences in simple FR measurements between the SVS R&D and the third party reviewers (Ed, me and AV Talk), I'm not surprised or worried that our max output data doesn't match. The data from three of us matches much better, and that's more important. Everyone can choose which data he believes.


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## Ilkka

Ed Mullen said:


> Yeah 0-2 dB is within normal variations between test rigs. But 5-7 dB? Nope - something is wrong. Like I said above, the only way to tell what is happening is to get both test rigs at the same location and calibrate them and take some measurements on the same subwoofer. Software glitch, flaky absolute SPL calibration, processor limitations - who knows.
> 
> The 12.3 woofer has a bit more (1-2 dB) midrange output capability than the 12.2, so you might want to add ~7.5 dB to each value for the 12.3. Again, it's bench racing but it might help as a comparative tool.


Has that been confirmed by anyone else than SVS R&D? And is that max output or 10% THD limited output? My own testing shows only 0.5 dB gain to 12.3 over 12.1 in max output. 



> Frequency (Hz) / 20 Hz Tune SPL (dB) / 20 Hz Tune THD (%)
> 
> 18	91.1	10.2
> 20	101.3	10.4
> 22	104.0	3.7*
> 25	105.8 6.4*
> 32	108.4	8.5*
> 40	108.5	4.5*
> 50	107.2	3.8*
> 63	106.0	3.6*
> 80	104.2	4.0*
> 
> * output was capped by the amplifier limiter before THD reached 10%


I got 108 dB @ 80 Hz for the Plus/2 (12.3), and that was with a sweep, so I'm willing to say it could have gone 1-2 dB higher with straight sines (and/or in cooler weather). That puts us (you and me) within 1.2-2.2 dB, even if I give the 1 dB gain for the 12.3 woofer. But even your number would still be 3.8 dB down compared to what Tom claimed.

And when looking at AV Talk's results for the Plus/2 (12.1), only 102 dB @ 80 Hz, it makes you wonder even more. And they used a very short 2.5 second sweep, so I doubt the VC heated up that much.


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## Manic Miner

Hi guys, I've been away attending real life for a while, and boy oh boy has a lot happened while I was away 

What struck me while reading this thread is that the entire discussion is based on JL's own measurements VS Ilkkas measurements of the Plus/2.

Now, Ilkkas and SVS' numbers on the Plus/2 doesn't match up, so why do we assume that JL's numbers would match 3rd party numbers?

If we are to give JL the benefit of doubt I think that SVS should receive the same treatment, especially since it's christmas : )


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## Chrisbee

If you can't send your test kit to each other for comparison purposes you certainly can send the same sub. (Not just the same model where small arbitrary differences can creep in) 

Pass the control sub around the various testers. Then each tester can do his worst (or best) and we can all compare notes. 

Logic suggests a compact sub with good extension, high SPLs and low distortion just to make the exercise fun. The JL 113 would seem the ideal candidate since it is proving so controversial.


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## Ed Mullen

Hi guys - sorry it took me a while to get back into this thread.



Ilkka said:


> Has that been confirmed by anyone else than SVS R&D? And is that max output or 10% THD limited output? My own testing shows only 0.5 dB gain to 12.3 over 12.1 in max output.


10% THD limited output over the mid-bass regions has increased 1.5-2.0 dB for the 12.3 over its predecessors. While I haven't confirmed it, you are probably correct in the assessment that that the max output has not increased as much. 

A better way to describe it might be the 12.3 woofer is cleaner than previous versions for a given sound pressure level and also has a slightly higher max output level (without respect to distortion) due to increased linear stroke and better thermal characteristics. 




Ilkka said:


> I got 108 dB @ 80 Hz for the Plus/2 (12.3), and that was with a sweep, so I'm willing to say it could have gone 1-2 dB higher with straight sines (and/or in cooler weather). That puts us (you and me) within 1.2-2.2 dB, even if I give the 1 dB gain for the 12.3 woofer. But even your number would still be 3.8 dB down compared to what Tom claimed.


Yep - there is definitely a discrepancy. I'll eventually be comparing my test rig directly to SVS' on the same subwoofers, so that will hopefully reveal more information. For now anything else would be speculation and I'm not taking sides - there could be a problem at either end. Without disclosing specifics, I do know they use a completely different method of calibrating and monitoring for absolute SPL than you/I do.

Since I got 104 dB @ 80 Hz for a 12.2 Plus, anywhere from 108-110 would make sense for a 12.2 equipped Plus/2. The reactive impedance load with the woofers wired in series is different than with a single driver, and the amp isn't quite 2X the power of a single 525 BASH, so the total power draw/output might not quite equal 2X a single Plus.



Ilkka said:


> And when looking at AV Talk's results for the Plus/2 (12.1), only 102 dB @ 80 Hz, it makes you wonder even more. And they used a very short 2.5 second sweep, so I doubt the VC heated up that much.


Going from memory, but I think their first round of sweeps were forward and didn't reflect the potential max output capability of the subwoofer in the mid/upper bass regions because they stopped the sweep when the sub started to bottom/fart etc. below tuning.


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## Ed Mullen

Manic Miner said:


> What struck me while reading this thread is that the entire discussion is based on JL's own measurements VS Ilkkas measurements of the Plus/2.
> 
> Now, Ilkkas and SVS' numbers on the Plus/2 doesn't match up, so why do we assume that JL's numbers would match 3rd party numbers?
> 
> If we are to give JL the benefit of doubt I think that SVS should receive the same treatment, especially since it's christmas : )


You're correct and I was hoping the thread wouldn't go that direction.....but a direct comparison to the Plus/2 by the OP combined with a large discrepancy in his data set vs. SVS' set the stage for a protracted discussion which ultimately focused more on the Plus/2 and various test methodologies and took the attention away from the F113 in the process (and JL doesn't deserve that). 

By all anecdotal accounts and objective data, the F113 is a great performer and is laying down excellent numbers and should be evaluated on its own merits.


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## Guest

can this sub keep up with really really fast speakers like electrostatics or zu druids?


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## bobgpsr

rean1mator said:


> can this sub keep up with really really fast speakers like electrostatics or zu druids?


Sigh! :rolleyesno: "Fast" subs opens a big can of worms. It will devolve to a discussion of ported versus sealed sub impulse reponse at the ported sub's tuning frequency. Basically if the ported sub's tuning frequency is low enough (less than 25 Hz) it is very hard to build a credible scientific/engineering case against any well designed low tuned ported sub. Impulse phase response is measurable. Ilkka has measured it. Music low freqs can only really be heard above 30 Hz. But since the JL subs are sealed they do not have to worry about any possible "slowness" or overhang of sound coming from a port. After that it is really only a matter of distortion characteristics and if they can keep their cone under control. I'll bet they do very very well at that. :clap:


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## tweakophyte

Hi Ilkka

Is this the thread you referred to?


---------
Quote:
*rubbersoul* wrote:  
_I to am curious as to your personal opinion on the JL Audio Fathom 113....I happened to buy one a month ago and recently as Dec 23rd actually got to calibrate it and use it and I was blown away. It has everything I think a sub should be._
_Feel free to sendind a PM._

_Merry Christmas to everyone!!!! _

_Frank:bigsmile:_

Quote:
*tweakophyte* wrote:  
_Now... was the JLA's distortion that audible? In other areas people have compared that sub to the Ultra... now I am doubting their ears _
----------------
I'll reply to these in the Fathom f113's own test thread.


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## Ilkka

tweakophyte said:


> Hi Ilkka
> 
> Is this the thread you referred to?
> 
> 
> ---------
> Quote:
> *rubbersoul* wrote:
> _I to am curious as to your personal opinion on the JL Audio Fathom 113....I happened to buy one a month ago and recently as Dec 23rd actually got to calibrate it and use it and I was blown away. It has everything I think a sub should be._
> _Feel free to sendind a PM._
> 
> _Merry Christmas to everyone!!!! _
> 
> _Frank:bigsmile:_
> 
> Quote:
> *tweakophyte* wrote:
> _Now... was the JLA's distortion that audible? In other areas people have compared that sub to the Ultra... now I am doubting their ears _
> ----------------
> I'll reply to these in the Fathom f113's own test thread.


Sorry, I meant this thread: http://www.hometheatershack.com/forums/subwoofer-tests/8152-jl-audio-fathom-f113-new.html

I will write the reply later today.


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## gopala33

first page thread i see screenshot the JL F133 ground plane resuits
i want check to see SVS PB13-Ultra ground plane resuits screenshot
give me link
thanks


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## recruit

gopala33 said:


> first page thread i see screenshot the JL F133 ground plane resuits
> i want check to see SVS PB13-Ultra ground plane resuits screenshot
> give me link
> thanks


Here you go... SVS PB13Ultra


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## lama67

What do think about the smaller F112? Is it good like the F113? I like the bass is not intrusive but dry and controlled.


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## tesseract

Welcome to HTS, lama67!

I haven't listened to either one, but I have read that some people prefer the 112 over the 113. 

I do know that 90% or more of what you hear will be dictated by the room, where you sit and how you compensate for any problems present.


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## Florianderton

Hello everybody!

I am new here in this forum and I read parts of this thread about the JL-Audio Fathom 113, and your links to the SVS PB-12 Plus. - Does anyone of you know about any measurements or opinions of the Adam Sub 2100? I would like to get more information about this sub - preferably in comparison to a Fathom 113 or SVS PB-12 Plus. What's your opinion about this sub?

Thank you very much, regards,

Florian


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