Howdy Jack,

How many frequencies did you perform decibel checks? For example, a 60hz check may not change. What about the rest of the range up to 20k hz? From my own unscientific observations, most of the sound change during break-in is in the upper mid-bass and higher frequencies... well above a standard 60hz test tone.

I don't know why I did not think of it before, but the auto eq settings on my denon receiver did change over time. Between the time when the speakers were new, and maybe 200 hours later, the settings are different. The interface on the receiver does not allow the user to see the granularity of the Audessy configuration(it uses a full range pulse-tone to configure), which would be nifty. However, when my 633T's were new, the receiver had them set to small (enabling a low pass crossover), and when I reconfigured at a later date, the receiver set them to full-range. Another noticable change was with the sub; over time, the receiver tried to lower the sub setting... it thought it was getting louder.  I did not pay close enough attention to the center and surround settings to note a difference.

Maybe someone from Aperion can have Ken Humphreys' (Aperion Speaker Engineer) throw in his 2 cents on the subject.

Good Discussion.

-James