Well, I made some changes today, and it seems MUCH better. I put the 350's back up front, figuring the combined output may be closer to the 600 in the back of the room. Since my 350's are only 5ft apart now (center of drivers) it is like they are ONE sub. So I calibrated them so when they are both on, they match the SPL dB's of the 600 when it is on by itself.
Before, I calibrated them individually, so when they were both turned on, the SPL was higher than the 600. Anyway, I reran Audyssey and now the distance is 9.5 ft. This seems strange, because this is less than the physical distance of any of the subs. But the Bass is SOOOOOOOOOO Intense now, it is like night and day.
The Darla "tap" and "whale" scenes in Finding Nemo are amazing, better than IMAX.
Fred, Audyssey can't run/calibrate the subs seperataly, as it is only ONE sub preout. I think the highest end Denon, offers independed sub preouts, in that case Audyssey would calibrate each one seperately.
When running Audyssey with this type of setup, they recommend that you keep all subs "in phase", and try to have them the same distance as possible from the first measurement (the one that calculates distance). Also, after calibration, you want to shoot for +-3dB on the receiver trim level. If your near the max or min of the Denon, they suggest adjusting the subs gain, and rerunning.
I just think that when you are dealing with different sub technologies, the internal ciruitry and delay are going to cause problems. DSP chips have a lot more going on inside than a traditional amp sub. It probably would be best to have identical subs.
All I can say is it has never sounded this deep and tight.
