Just about to upgrade my receiver from an old 5.1 Yamaha to a 7.1 Arcam AVR 300 (much help from reading a million threads here..thank you). I have a smallish room with the two viewing/listening chairs up against rear wall directly facing the plasma TV. I was originally considering having two in wall speakers cut into the back wall, one each behind and perhaps just above each chair. After reading many threads here I am leaning towards Dipole rear surrounds or something along that line, IE Axiom QS8's. Question is.. do I put them directly behind listening position as in inches behind head (to create true rear sound but possibly too close to create sonic spaciousness),or would it be better to place them slightly higher? Thanks for your replies whether based on experience, word of mouth or an educated guess.