Can you clarify? You mean a single QS8, or a pair of M2's, even if there is less than 4 feet?
If less than 4ft QS8's either a pair or a single, I ran a 6.1 system for years and it worked very well as the QS spreads the sound out very well, but with the new 7.1 movies an extra rear channel might be warranted.
If the distance is more than 4ft then I would recommend some M2s or M22s as the distance will allow the speaker to spread the sound out and also throw the sound out towards the listening position. Although alot of this is personal prefference, some people still prefer the QS all the way around.
