Warrior, how would I show a graph without audyssey? Would just turning it off in my AVR do that, or does it still apply some eq functions to the sub channel?
KEW's advice should work, you just have to tell the Denon to use the subwoofer.
To be clear, the measurements you posted are with the sub in the corner nearest the couch, like in the pic, yes?
What is the LFE crossover? (couldn't find it mentioned)
It is very difficult to satisfy all seats with one sub, even in a rectangular room, that said, you're measuring pretty well with car subs! And a car sub that is snuggled next to a giant absorber - the couch.
As I recall, the X4000 has preset bands of EQ, yes? Are any of them even close to 90 hz? You may also be able to boost a few dB that way and minimize the null a bit if you leave the sub where it is.
Assuming your LFE crossover is above 90 hz: If the sub were moved to where the DVD rack is, to the left of the TV, it might help cancel out most of that null, the wavelengths of those frequencies should put most of the null behind the seats. Your seats should be just far enough forward so to limit the excitation of the 3rd length mode, but there in the lies the trade off with one sub - You can't focus that pressure source to all seats at all frequencies. Measure and see!
Because there is only one sub, moving it can solve one problem and create more. But if you do try the left corner just keep it close to the walls, use your ears with familiar content to adjust the distance in
inches to that corner, locating the Left loudspeaker to the right of the sub, nearest the TV.
Should you add more subs, I'd suggest getting smaller units that can be hung near the ceiling since your floor space is limited.
Sorry for the bold, trying to make it easier to read.
