OK, I think I have learned my room and ARC measurement process to claim this set as final at this time. One thing I have learned is to read the manual carefully. On page 28, it says:
"Ideally, the front speakers' high-frequency drivers should be at approximately the same height as the listener's ears but if they aren't and the result sounds dull or bright, microphone height will have to be adjusted and measurements repeated."
This turned out to be spot on - my last set of measurements was made after I adjusted the mic position to be EXACTLY my ear level when I am seated on the sofa (this turns to 37 1/2''). I have also left about 10'' clearence from the sofa and chair cushions. This has resulted in much smoother measurements with much less correction above 2kHz than before. In full range, L/R bass levels were left almost untouched (apart from correcting dips at 60Hz for L and 130Hz for L/R speaker).
Another thing I learned is to never question jayray
- he kept hammering home the message that many people try to tweak ARC and eventually return to the original set of targets. And tweak I did - bass from auto to flat to 8th order back to flat. And frequency limit from 5000Hz to 200Hz to 1kHz to 2kHz (like Kal Rubinson when he reviewed MRX 700) and back to 5000Hz. I also played with room gain and always returned to whatever ARC computed. And of course, I didn't touch levels.
That does not mean I have nothing left to tweak. For example, the resulting sound is so clean and transparent that I managed to hear clear differences between connecting my HTPC via HDMI vs Musical Fidelity V-LINK + Toslink vs V-LINK + digital coaxial. In fact, I can hear subtle differences between two digital coaxial cables (both Monster Cable Video, both solid core with extensive shielding). I also hear differences when cable box is connected via Toslink vs HDMI audio. You see - there is always something to tweak
One thing I may still do is put my surround speakers on taller stands. Right now they are on 24'' stands, which puts their tweeters at 33'', while L/R tweeters are at 40''. Putting them on a 30'' stand would even things out and help them clear the sofa back.
I am now going to enjoy MRX without playing with ARC for a while. If I can fault the sound at the moment, the only thing that comes to mind is that it is possible that my B&W 800 series speakers can use a bit more current and control that MRX can provide. It is definitely not an issue of power, just current and control. Again, it is possible that Kal Rubinson's combination (MRX + Bryston 9B SST) would offer more solidity in the bass and lower midrange. I may do it at some point in the future (I always wanted 9B SST
, but I am definitely not desparate to do it right away. On the positive side, I have been told that B&W CM1 and 805S have similar crossover and should show family resemblance. My old Denon receiver left me wanting, but with MRX, front to back pans sound very natural and without any change in timbre (and I am thrilled that CM1 can nicely handle 60Hz crossover point).
So there it is. My levels are: