I was going to post a new thread on this until I did a quick search and found this one titled almost exactly as I had planned on titling the new thread.
So I'll just add my comment here instead as it seems that this auto-calibration comparison seems woefully elusive, or perhaps those who might conduct one do not find it a worthwhile endeavor. At any rate, it seems to be of great interest to those of us who do not have ultra-ideal system/speaker layouts in acoustically perfect rooms, and at least IMHO, the room calibration functionality of any given AVR can truly make a difference in these much less ideal acoustic situations. Whether or not one is particularly better than the other well... that's the big question, but after now having had experience with MCACC, Audyssey MultiEQ XT32, and most recently, YPAO, I have firsthand experience to know that they certainly don't all
run the same, and my end results have varied from platform to platform.
I've made two calls recently: One to SVS (makers of my speakers) and the other to Yamaha (as I recently bought the RX-A2060BL model). I asked both about most of these calibrators tendencies to set even small speakers to large, despite their size and FR, and the best answer I got was from the SVS rep. He told me that this is commonly due to placement and possible boundary gain influencing the mic during the sweep checks; resulting in a lower registered response than what the speaker may actually be capable of, and the mic isn't able to tell the difference. At least given my layout, with my couch up against the rear wall, he said that made the most sense to him and it makes sense to me. He suggested I move the mic out to a position that is actually a bit forward of the MLP and see what happens. So I did, and it still set them to large. MCACC also always set these same speakers to large and only Audyssey ever got it right and set them to small. This in of itself isn't a huge deal, I was used to going back in, setting them to small post-calibration with MCACC and moving on. I do the same now with YPAO.
Getting into the finer details of each, it seems that each one of these three main ones do offer some unique corrections, with MCACC (at least in the higher end Elite models of 5-10 years ago) seeming to top the list of additional corrections it employs during its calibration.
MCACC seems to be a bit more explicit about these features with listed offerings such as standing wave control, group delay control, full band phase control, sub eq, and reverb control, while both Audyssey and YPAO showcase the EQ, level and distance settings, but these additional corrections seem to get lumped into black boxes of mystery known as "XT32" (for Audyssey) and "R.S.C." (Reflected Sound Control) in Yamaha's case. Strangely enough, when I asked the Yamaha rep about R.S.C., he quickly stuttered a response that the question was above his paygrade and that he would have to elevate that to a Level II or III support tech who would call me back. ??? So that call back never happened, and my questions about it go unanswered. I like the fact that with MCACC it would actually show all these things it was doing while it was doing it, so I at least had some kind of tangible evidence that it was doing more than simply pushing around a few EQ sliders.
I can also now safely say that, while my new Yamaha powered system sounds good, MCACC seemed to do a much better job at taming my difficult room than either Audyssey or YPAO and I have run both of them many many times in many different ways. I used to be able to just run MCACC once, reset all my speakers back to small, maybe nudge up the sub level a few db and call it a day. Now I'm experimenting with different speaker positions, room treatments, even replaced my center channel speaker all in the pursuit of taming these nuisances from my bad room. MCACC seemed to correct for them very efficiently; so far I cannot say the same for YPAO/Audyssey, though with some experimentation I've at least gotten YPAO to somewhat get me there; then I fine tune it the rest of the way manually. It still doesn't get the system as good sounding as MCACC ever did on its own. I would really like it if Audyssey and YPAO showed us a little more of what's behind the curtain when its running their calibrations other than just showing us some eq curves, distances and levels. If YPAO R.S.C. is doing a damn thing to address phasing or impulse response, it certainly ain't giving up its secrets. In the Navy we had a phrase, "Well I guess I'll just push the old 'I believe' button!" That kind of applies here.
I know this is all entirely anecdotal and subjective; maybe not quite the scientific analysis/comparison being sought, but until that happens at least it's a real world comparison between the three main ones out there on the mass market from someone who has direct experience in all three.
