I recently purchased an Axiom HT speaker system to use with my Denon 2802 receiver. I wasn't sure about the placement of the rear surrounds and the rear center, all three of which are QS-4s. My room is 12 x 19 with the listening area approximately 12 feet from the front of the room. My question is at what height the speakers should be placed, and how far behind the listening area. (The rear center will go on the back wall, I'm just not sure at what height.) The ceilings are just over 7 feet, and I was leaning toward placing the rear speakers close to the ceiling, but I was looking for some guidance. Finally, where should the sub be placed? Should it go on the front wall near the M3ti's or can it be placed on one of the side walls. Thank you in advance for any guidance that you can give me.