As to your theories:
What I am most interested in is seeing if we can verify one way or another what actually happened. Let's try to test out desertdome's theory. I know we were able to reproduce the same results on three days with the CHT subs. Friday test setup (no Audyssey), Saturday's meet (with Audyssey), and Sunday's retest (with Audyssey). I don't agree with desertdome's synopsis that the CHT subs were distorting the whole time and I don't think the other attendee's subjective commentary lines up with that. I talked with Luke Kamp, stitch1, and carp in the last couple days and asked them if they thought the CHT was distorting the whole time and they all said no. Stitch1 even said the CHT subs sounded pretty good to him. I’m not saying desertdome didn’t hear sound he didn’t like, I’m just saying "distorting the whole time" is seemingly an exaggeration based on hearing them distort a few times. I personally thought the CHT were only distorting on the extreme dynamic peaks in the movie section (not every clip) and at the bottom end of the music section's sine wave. Others, who were in attendance, can probably chime in with their thoughts on the constant distortion question.
The songs and media we used are all linked in the first post which includes the sine wave. I'd prefer to provide the actual original clips to you via e-mail if you want to do some actual testing, which should be more accurate for testing, because the clip I posted was combined/encoded to be a single MP3 so I could easily post it for others to demo, but in combining those tracks they had to be re-encoded which may affect the sound/dynamics of the source. My Onkyo settings were all listed in post three, main volume settings in post one. The iNuke DSP settings are listed exactly, the only big variables are the room, and what Audyssey did/does. But the frequency response measurement was captured before Audyssey in Friday nights test, and then the same DSP settings were applied and the frequency response capture showing what Audyssey did is available for both Saturday and Sunday's retest. There aren’t any mystery settings that are missing to repeat what happened. So we should be able to make more sense of this with some further testing.
Do I understand you have a iNuke DSP 3000 and a pair of CHT 18.1 subs? We, and by that I mean you, could repeat the tests if you are willing. Ideally you'd do the tests once in bridged mode, and once in dual mono mode. Yes this will require rewiring your neutrik and would likely be a several hour ordeal.
As to setup - we ran Audyssey MultiEQ XT, turned the subs up 3dB on each channel (my Onkyo TX-NR1007 has two discrete sub outs), set the crossover for 100hz for mains and 120hz for subs. Turned off Dynamic EQ. Playback levels were at -10dB for music, and -10dB for movies with the exception of the last few tracks.
This is the information I was trying to share with Craig Chase. He had the iNuke amp. I asked him to test it on his own and he was unwilling to. If you repeat this test in your own home you should encounter the same thing.
Here is our retest data
http://www.avsforum.com/t/1387178/archaeas-kansas-city-blind-subwoofer-shootout-2012/330#post_21515107You might ask how could the test be relevant in different rooms?
Because I know from Sunday's retest that Audyssey didn't change the sub's response much at all in my room (because we already made the results so flat with the iNuke's DSP) - therefore you SHOULD be able to use the exact same DSP settings, not involve Audyssey, set the SPL levels manually, and experience the same results on the same media as we did. If you experience the 'bottoming' out sound on the sine sweep with 8 ohm dual mono, but don't experience it on bridged 4 ohm load then it could clear up some of this controversy. I still have all the omnimic captures from the meet. For verification that Audyssey didn't end up changing the frequency response much from my DSP settings in my room check out the following screenprint: Audyssey actually lowered the output a dB or two at 20hz over what we had done with the DSP.
The top two sweeps are with the iNuke - with and without Audyssey
The bottom four sweeps are with the Dayton amp - with and without Audyssey and with and without bassboost button pressed.Let me ward off one question - NOTE the above Sunday restest capture was done from one listening position and averaged 10 times. Versus the meet frequency response captures listed on the first page of this thread that were averaged from the multiple seats of each listener. The two graphs cannot be compared. But the point is that Audyssey didn't have much to do, and didn't do much to the EQ we dialed into the iNuke's DSP. So blaming Audyssey for this 'issue' is likely misplaced blame.Were the bad noises on the deep notes and dynamic peaks solely the amp's fault?
FWIW, I will remind the reader that HuskerOmaha told me the CHT 18.1 subs were the only subs he was able to recognize during the blind meet audition based on those bad noises because he was familiar with their bottoming out sound in his room from his usage on his own pair. He was not using a iNuke DSP 3000, and IIRC had a Dayton SA1000. I will also point out that the Dayton amp was tested on Sunday in various configs - with and without Audyssey - and while not producing the bad noises the Dayton amp sounded notably anemic for the deepest material to both the sub owner and I in my room at the standardized playback levels used during the meet. It was also discussed and agreed upon by both the sub owner and I during Sunday's retest that the 18.1 subs would have most certainly scored worse in the blind testing using the Dayton in four ohm bridged in my room, which was Craig's standard selling configuration at the time. It would have most likely scored lower because the deep bass was literally missing when the subs were coupled with the Dayton on the material tested, and thus a sub that was subjectively rated as having little depth of note by the majority of the auditioners, would have had less depth in comparison to the other offerings. Well then what other amp should we have considered? We couldn't use the standard paring Dayton amp because as I said it sounded sufficiently weaker to both of us. What about other popular amps? Well we shouldn't use the EP4000, because the EP4000 was said to sound poor on the CHT 18.1 pair by three notable CHT forum members as noted in this thread.
Specifically - diamondelts and mktheater said the EP4000 sounded bad on 18.1 as quoted here
And tesseract67 said the EP4000 wasn't any good as quoted here:
At a certain point you can't help but wonder if an amp 'sounds bad' or like it sucks "monkey balls" when it delivers power at the lower frequencies the 18.1 subs can't comfortably handle? In that instance the amp should not take the blame.So derrickdj1,
Would you consider mimicking our iNuke DSP (post 3) and AVR volume settings exactly and see if you can reproduce the 'bottoming' out sound at our same settings in your room using dual mono 8ohm? You will not run Audyssey for your tests after applying the iNuke DSP. Once we have established that I think we could learn a lot from there. What my DSP setting sounds like, or measures like, in your room is irrelevant to this test proposition. You are only attempting to mimick my settings in your room. What is relevant is answering the question - do the CHT 18.1 subs make a bottoming out sound at 8ohm dual mono using the settings, on the sine wave sweep, and yet not exhibit that behavior at the same exact SPL level and DSP settings when bridged to 4ohm. I'd glady do it myself, but I no longer have the CHT subs available to test, though I still have the same iNuke amp.
Perhaps unrelated - perhaps not
We possibly may have heard this same phenomenon on the 18.1 VS at the HuskerOmaha 2011 meet on higher 30hz content in the Kid Kudi song and the Flight of the Phoenix track - both very heavy in 30hz content.
The 18.1VS uses the same driver in a vented alignment. Post 432, 433, and 438.
and continued discussion here:
http://www.chasehometheater.com/forum/showthread.php?t=3975&page=52Edited by Archaea - 12/15/13 at 12:39pm