Sirquack,
Yes, all Denons will drive the 4-ohm M80s without any hassles, and so will all H/K receivers. Yamaha in the past has been iffy re 4-ohm loads and I'm unsure about the 2400 and 1400. Ask Yamaha, and be sure to ask, "Will the Yamaha 2400 drive a 4-ohm load at full output, without current limiting?" Stay away from Pioneer if you want to drive 4-ohm M80s.
You will likely need to run two subwoofers, given the huge room volume (9,500 cu ft.). The subs don't care where you sit. They simply have to pressurize the total room volume they "see". Anyone I know with a room that large is running two subwoofers.
Auto-EQ is a crock and can make good speakers sound bad. Turn it off. Use the auto-level setup, etc. THX has certain requirements for power amps which are worthwhile but in receivers I don't think it's worth it.
If you are male and over 30, it's extremely unlikely you can hear above 16 kHz, unless you grew up in a forest with no horrible noise-making leaf-blowers and other such devices around. Besides, there is very little music content of importance above 15 kHz-- a few harmonics of violin, piccolo, and cymbals.
I think you mean B&W, not B&K. The B&W 703 is comparable to the Axiom M60ti. As to the QS8s, you can explain to the salespeople that a dipole/quadpole/bipole surround is used to mix movies in mixing studios, because the whole point is to mimic the ambience of reflected sounds generated in large cinemas by rows of surround speakers that line each side wall. In the relatively small rooms in homes, if you used direct-radiating surrounds, there is not enough reflected information to effectively mimic the soundfield of a large cinema. But if you use a multidirectional radiator, you generate a rich soundfield of ambience that will extend to listeners who are not in the sweet spot. Direct-radiating surrounds are fine if you never move out of the sweet spot.
I even prefer QS8s for multichannel music reproduction as well.
Regards,
