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Shouldn't the subjective performance be the most important factor at the end? Though subjective and objective performance go often hand in hand.

Sure thing Parker. It's funny how these threads often have the tendency to derail. :)

Sorry about the misunderstanding, I only ment exact as what it comes to THD testing. There are couple J. Johnson's old reviews containing some THD data, but other than those, Ed's reviews are pretty lonely. edit: It seems though that the discussion is heading towards dead end, so we might as...

Yes, I'm sure they would let Nousaine test their subs, after all, he's the one who invented the 10% THD test. But in any case, I would like to see more professional reviews with thorough measurements on SVS subs.

Robb, As I know that you are somewhat connected to SVS, I think you are a little bit biased. But yes, I made a few assumptions. I'm sure that's not the case, but manufacturers should understand that their products can be put under different kind of tests, not just under the ones they self...

I think there would be many 3rd party testers available, but if you require that the testers must use the same specific tests for measuring different variables as you self do, it will be a much harder job to find them. IMO it's not even fair to other manufacturers.

No they haven't, but still you used them as a "backup" for your own opinions and methods. But as far as I know, no one except Nousaine has used the 10% THD test. I think we are now confusing two different things, maximum output at different frequencies before audible distortion, which the new...

I respect the work you have done for sure. But could you tell which of those gentlemen have used the 10% THD test in their reviews besides Nousaine?

I'm extremely sorry about that. I do remember seeing that comment, but it wasn't from you, somebody was just misquoting you. Here's what you said: "In comparison to the PB10... In terms of sheer output... SB12plus will have slight advantage >45-50hz. In the 40-50hz range it is close. And...

I believe one major reason for its claimed musicality (I haven't heard it) is indeed its maximum output capability above ~40 Hz. Although Ed's 10% THD data doesn't clearly show it (one reason why I (and recently Ed too) prefer other way to measure THD), I believe its THD levels are lower for...

Hi all, I was too a bit disappointed when SVS published the frequency response for the SB12-Plus. The final roll off looked almost identical to their vented subs, which is IMO too steep for a proper sealed sub. It just takes away the only real advantage sealed subs have over vented subs -...

Yes, http://www.hometheatershack.com/foru...t-results.html Check also other measurements, http://www.hometheatershack.com/forums/subwoofer-tests/

http://www.dvdplaza.fi/forums/forumdisplay.php?f=157 The results are up, enjoy. :)

It is a big jump, but I would like to cover as large amplitude range as possible, but I don't have time to use very small steps...for example 90, 95, 100, 105, 110 dB. But we'll see...

Yes, naturally it will be 2 m GP. And I wouldn't be so sure about the other one... ;) There aren't many, but there are some.

My next measurement session is due to happen quite soon (in 2-3 weeks), so after that we will be having loads of comparable IMD data for many different subs. Including both low end and high end subs. The fundamentals will be 30 Hz and 72 Hz. I will probably be testing IMD at three different...

Thanks Robb. AVS changed since they became the AV Scientology instead of AV Science. :thumbsdown: Luckily we still have other good forums.

Steve's question is a good one and that is one reason why original 70 Hz was chosen. 30/65 Hz could be possible, but 2f1-f2 yields a 5 Hz component. I think the lowest possible would be 30/71 Hz.

Well naturally some IMD components are harmonically related, but it doesn't matter and can not be avoided, since the equations are what they are. Important thing is that they don't match with any harmonic of those two fundamentals.

Guys, I'm much more comfortable naming all the tested subs after I start making GP measurements. It is essential that the environment doesn't affect on the results at all and unfortunately I can not promise that while indoors. The purpose of this thread was to rise some discussion about IMD...

Yes! Sorry about the geek speak. ;)

By definition harmonical tones are multiples of the fundamental. And the THD is being calculated by comparing the total SPL of these harmonics to the fundamental. 30 Hz and 70 Hz (we can also try 30 Hz and 78 Hz) played at the same time create a number of inharmonic tones (inharmonic to...

OK, I don't think port noises will be a problem even now. You know that single 6" vent has more area than two 4" vents. So for example when comparing to Ultra/2 in 20 Hz tune...

Wow Steve! I thought you were joking about building it up only in one day. :) That is one sweet looking vented box. I don't know how much bracing you put in, but if the final net volume is more closer to 7 cu ft and you used the vent length I suggested, Fb will be around 16.7 Hz. But of course...

Here is the same list for 30 Hz and 70 Hz fundamentals. 100 40 10 110 130 170 200 80 240 160 180 20 50 150 230 270 50 250 190 310 300 120 340 260 220 20 380 220 And harmonics. Harmonics 2nd60140 3rd90210 4th120280 5th150350 6th180420 7th210490...

Here are all components up to 6th order created by 30 Hz and 78.5 Hz fundamentals. 108.5 48.5 18.5 127 138.5 187 217 97 265.5 168.5 205.5 11.5 67 175.5 247 295.5 41.5 284 198.5 344 325.5 145.5 374 277 254 37 422.5 228.5 And here are the harmonics of those two...

There was a pretty strong 10 Hz component at highest 120 dB level. For example Ultra produced around 82 dB there (~1.25% IMD).

That is a good suggestion. But like I said to Dave, when using 30 Hz and 70 Hz fundamentals, 2nd and 3rd order components are "clean", so if we need to omit for example two components from the 4th order components, it won't affect on total IMD at all (maybe 0.0x% at most).

I'm not sure IMO would help that, but what ever... :)

Why's that? Of course I checked the noise level and 50 Hz hum was at low level. It doesn't affect on IMD -% at all. And at higher test levels actual 50 Hz component goes higher than the noise.