Help me out please. I am working on my basement and going to make a HT room. Would the rear speakers (3) be too far away? Should I mount them at hear level or higher? Please please please....if ANYONE has ANY input or suggestions PLEASE feel free to add. I am going to run a 2" PVC in-wall...

I'm working on building my media room in my basement. We've almost finished getting the walls put up in place so I'm starting to think about my wiring etc. for the media room. my dimensions are roughly 12'6"x21' for the room. At the back left of the room is where I'm situating my A/V...