+1 concurred. I too find it amazing that such a small change has made such a big difference, but there is no doubting what Murray is hearing and he has tested it with his 'test passage' from The Town and is very happy with the result. HST, I too would love to see the measurements that reveal the change.
Now some may not believe me but the problem is fixed, that very same horrid "tone" is now the same in every row, let me explain.... That "note" was soft and low in the middle row but when I sat in the back row it was loud and would warble and resonate, it was absolutely intolerable!!!
Last night I started to raise the crossovers on different groups of speakers rather than moving all up to 80Hz. Remember I left them were Audyssey found them below.
Front wide 70Hz
Front high 40Hz
I started with the front centre moving it up to 80Hz, the "note" was the same. I then moved up the front left & right to 80Hz, the "note" was exactly the same (what the heck I think????)
I raised the wides to 80Hz still no change....
The I started on the front highs raised them from 40Hz up to 80Hz, OMG the "note" started to resonate again, what on earth is going on here I think....I turn them back down to 40Hz and the "note" from the Town is great again. I then try the surrounds moving them from 40Hz up to 80Hz, the "note" is horrid again.... I then move the highs and the surround's up to 80Hz and the "note" is out of control, exactly the shocker Ive been listening to over and over again for the last 1.5 years!!!!
Ok the light bulb is coming on in my head...... Im starting to feel happy as I now know whats causing the problem with the so called horrid "note", frequency in the "Town" and the boom at the back wall, which has now been eliminated completely though the tests. I moved every speaker up to 80Hz except the highs and the surrounds, the sound, the bass, the boom and the "note" is superb in every row, all the three rows sound exactly the same to my ear. The horrid back wall boom has gone forever!
Now my thoughts came down to the speaker design of the surrounds and highs, interesting that they are all the same and not used anywhere else in the cinema. Lets take a look at them and maybe you guys might tell me why is it these four speakers introduce the boom and the horrid frequency in the "Town" when I start to move the crossovers higher than 40/50Hz?
We are dealing with four top of the range Klipsch THX in ceiling THZ KL-7502 speakers. Enclosed design tuned port chamber, feq response 45Hz - 20kHz.
Is there any possibility that since these are the only speakers in the cinema with a port design that the port creates the problem? Everything else is sealed including the 6 subs. The room also is sealed.
Ok I know we still don't have measurements yet, but at the end of the day after doing hundreds of Audyssey EQ's trying to EQ the "note" and boom out of the room/back row, all along it was four speakers causing the problem.
Every speaker is now set to 80Hz except the four ported ceiling speakers. The sound is magnificent throughout all the three rows, Im over the moon!
And finally the "note" in the back row is hardly heard, its soft and hard to hear, there is no LOUD warbling resonance from it, spectacular!!!
I thank all the guys here especially Keith and Jerry for offering help and ideas. I thank myself too for not giving up. I never thought I would discover this even though I don't understand it, but its fixed. Who cares if the highs and surrounds arnt at 80Hz, I certainly don't, but the rest of the speakers are;)
Guys please chirp in if you know why the ported highs and surrounds don't work well set higher than 40/50Hz, considering they go down to 20Hz.......