Ditto what they said.
If aesthetics dictate that you must place the couch up against the back wall, then the QS4 should do just fine. It does a very good job of dispersing sound. This, coupled with the down-firing mid-range woofers means that you won't miss surroudn back pans that might fly right over your head if you were using a traditional direct firing speaker.
I agree with sirquack, though. If you can afford to give the couch some breathing room from the wall, the space will pay off in a much nicer and fuller rear section.
Congrats and welcome, again. Also, factory outlet is highly recommended. That's how I did mine. Not a scratch on a single piece.
Pictures not recommended, they are required...Have fun building!
