Jordan, as I said above, unless your listening room size and your distance is very substantial, the QS4s should be fine for the side surrounds. So if that applies in your situation and you have enough room behind you for a back surround effect, the same standard would apply and the QS4 should also do the job there. Rather than 6.1, however, you should consider 7.1 for the stereo back surround processing of 2 and 5 channel material that DPLIIx, etc. does, as well as possible future discrete 7.1 recordings you might get.
