To be a pain, I'll point out that you should avoid having your listeners at 15ft from the front and back walls. Land of the Null! But I would not worry about the Qs without a close reflective wall. Put them as directed on the sides of the listeners and the will perform as advertised. The question of rear-surround is more difficult.

Some in your situation have gone with direct radiating speakers on the back wall, others use Qs back there, but some say the benefit of the Q that far away is lost and the cheaper direct equivalent is enough. Others have done mid-room setups for the rear speaker where the rear wall is actually in another room and suspect their spouse and guests don't want to hear the helicopter at 105db as they cook!


Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire