my 2 cents.....
Just got a denon 987 and used audessey to calibrate my PC Ultra and MBM-12.
The problem I was having was that the auto calibrate would turn the Sub managment level to -12 out of -12-12+. This was with following audessey's recommendation of turning the gain on the subwoofers to halfway up prior to calibration. -12 is next to off. So I figured the subs were too powerfull with the gains set halfway up initially, So I backed them down 1/4 to about 10 on the dial. Did the auto calibrate again, and wound up with -12 in the Denon. I then manually did Spl measurements and found that the MBM was boosted over the SVS. Probably because the SVS wasn't really accounted for by the tones in audessey. In a way this was good, because then audessey would do too much to equalize the lower bass below 50 hz. My SVS was crossed to the MBM at 50hz. The MBM was crossed in the AVR to 100hz. next up I did some tone spl readings with a CD I made up and recorded various Frq's. I found that I needed to turn back the MBM gain a bit, down to about 9:45 and boost the Ultra to about 12 (half way). Running the FRQ CD I found that that most of the spl readings were pretty close, not flat by any means but good enough for my taste.
Curious, I ran the speaker tone test in the Denon and everyting matched perfect. So the audessey was spot on for the speaker calibration just not the sub. But because of my adjustments, the sub got matched perfectly.
Now to run every speaker at the exact spl including the sub, the denon remains at -12 subwoofer, this includes having decreased the gain on the MBM and increased the gain on the PC Ultra. Because I like the low end boosted for a nice house curve and personal taste, I adjust the denon sub level from -12 to -9 for HDTV and for DVD's to about -7 for Dolby Digital. DTS around -9.
Like a previous poster stated, if I leave it at -12 the auto-on, on the subs won't kick in until the volume is boosted high and then backed down again.
the setup now Sounds really good but took alot of measuring and trial and error.
Mainly because of the 2 Subs crossed at different points.
I found that Audessey was pretty accurate in its readings including tones and distance. Not sure if I like the sound when it's activated though. Seems to push mid-bass alot and roll off the lows by about 3 dbs.
Just my thoughts....