I ran through the Audyssey setup on my Denon AVR-519 using all 6 available mic measurement positions, and it sounds fine except that the center channel is WAY too low. I can hardly hear the dialogue when watching movies, yet all the other sound effects are LOUD. I literally have to change the center channel's level to +12dB in order to balance it out, but at the same time the dialogue coming out of the center channel is not crisp and clear. It's a little too bass heavy and/or lacking in treble.
I've seen some forum posts out there referencing the Audyssey-configured center channel being too low, and sometimes muffled sounding. Some even suspected it might be a Denon-specific issue, but I never saw a definitive solution. Any ideas?