Hmmmm...I dunno. Playing M100s off my Onk vs ADA-1000 or ADA-1500 didn't make any difference at normal listening levels. That's at 14 feet away in a 4200 cu ft room. 60% or more of the energy in music is below 100Hz or so. If the subs are doing all that work, the AVR doesn't have to.
I'll tell you what made a big difference for me moving from M80/150/QS8/600 v2 to passive v4:
1. Sealed Axiom subs. Just the 800 alone cinched it. It cleaned up the mess the 600v2 was spraying all over my room.
2. M5 or M100. Even M2s are much better than M80v2. Soundstage, imaging, mid-bass, mids, highs,...everything!
3. 160
4. QS10
The actives upped the emotional satisfaction by giving me an illusion of room boundary/soundstage expansion. They also offer higher image resolution and improved placement of those images on the stage. Both of these are major improvements over the passive system described above.
Now I need to work on erasing the boundaries through proper diffusion. That though is just gravy and me being particularly picky.
