4 large is GREAT!
I have a Harmon Kardon 7200 A/V. It has 7 channels at 100w per, and also can do 7.1 or can go channel stereo.
Fronts Infinity Overture 3's each has 250w powered sub
Rears Infinity IL60's each has 500w powered sub
I used my friends Velodyne 1215 sub (Idont have one yet)
Center Infinity IL25
Putting the fronts to small, rears to Large and sub to (Lft, Rt, & LFE)
also adjust the speakers. Fronts at 4+ Rears at 8 or 10+ center at 5+
This is the key to make the backs play loud. And keep up with the Fronts.
I played Fleetwood Mac The Dance DVD, it has tons of base in it. It sounded great in HK 5.1, but not as well in stereo.
But then I played Eagles CD hell freezes over Track 6 (Hotel California) and it blew me away in stereo. Please try these two Youll love the sound even if you dont likr the music.