I have a room that is unfinished above the living room. The room is 15 x 21. I want to put in a 7.1 setup with 340 SE L/C/R, 170 SE Surround/Rears. I have attic space on all sides of the rooms and I want to hide the speakers within the walls. I can build cabinets to put the speakers in. If I allow enough distance (rear ported speakers) behind the speakers, will this still mess up the sound quality.

Scott