Not sure if Alan still stands by this but here’s what he has said emphasis mine:
http://www.axiomaudio.com/how_to_buy_receiver.html
Auto-Setup and Calibration
Even inexpensive AV receivers now have some type of auto-setup mode, with many including a supplied microphone and auto-calibration/equalization circuit (Audyssey is very common) that claims to adjust the frequency response of the system’s speakers to match the room’s characteristics.
While the auto-setup modes are initially useful for first-timers, they are still prone to error, sometimes setting speakers that are small to “Large” and making errors in speaker level settings of 4 dB or more. You should still do a manual check using a sound-level meter and a pink-noise signal.
Unless you have really poor speakers, I recommend you turn off the auto-EQ circuits. They may help smooth out the non-linear spikey frequency response of poorly designed speakers, but with really smooth linear speakers like Axioms, they often degrade sound quality.
Here is what Alan has said about room treatments:
http://www.axiomaudio.com/roomacoustics.html But isn't that why they call it Audyssey
Room Correction? Its primary purpose is to compensate for room shortcomings, not poor speakers.
Philosophically I understand why Alan wouldn't want anything to mess with and/or change the sound of a nice neutral, linear speaker, but a bad room (acoustically) is essentially doing just that. Audyssey simply trys to correct whatever effect the room is having on the sound.
A properly treated room is always preferred, but many are unable or unwilling to go that route, so Audyssey offers them an alternative. The results will vary from person to person, so just consider it another tool. Use it if it helps with the overall sound, otherwise turn it off. You get it included with the receiver either way, so it doesn't cost anything to try it out.
