You will find that "official" specs for surround speakers in a 5.1 setup say to put "dipole" speakers directly to the side of the listener. Real world experience shows that while this may look good on paper, it doesn't always reproduce the type of surround field that YOU may particularly like. This the recommendation to look at putting the speakers 2 feet behind you. That advice does help to put the surround sound more "behind" you.
Now, add the fact that the QS8 speakers are NOT dipole, but are quad-pole. I think that they are the only quad-polar speakers out there, and they create a very large sound field, which also means that it is possible to "fudge" the speakers back behind you a little bit to get more of a surrounding effect that is not always good with a dipole from someone else.
Anyway, now back to the back wall idea. I had my rear speakers on the back wall of my setup with the seating right against that same back wall. There were no side walls within a reasonable width, so this was my only option. The QS8's did great. If you click on the link in my signature, you will get an idea of my placement. I had to turn the audio levels up for these speakers a bit, and looking back it would have been nice to have them a little lower and closer, but again, as you will see in the pictures, there were windows in the way.
I have since moved everything into a dedicated room, and the speakers are on the side walls. It sounds a LOT better, but I think that a majority of that is because I now have a smaller air volume to fill with sound, so the audio doesn't "leak" everywhere else in my basement.
Hope that this helps to some degree.
