I did come across the following comment by Alan Lofft in his article on choosing a receiver:

How to buy a receiver
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.

2-M60s, VP180, 8-M3s, SVS 20-39PCi, DIY Sub, 8-Shakers, JVC RS45, Anthem MRX-1120