It's you room Mojo.
The QS8's are pretty forgiving for less than ideal placement options, but you do need two or three feet minimum behind you for the back channels to do much. I had a 7.2 using QS8's at the sides and backs, and the backs were about 3' behind the seats. I liked this set up quite a bit. I never had a desire to change until recently. Now I have a 7.4.2 Atmos set up and love it. With a good Atmos recording, the sound is fantastic. I literally feel like I'm in a bubble of sound. Well worth the expense and aggravation to set it up.
