i have my rears right up next to the ceiling, over a slidding patio door, tilted down aiming right at me. and my sides are about 5'. all are measured the same distance from my head. it sounds just fine. are there a better sounding positions ? perhaps, but i think it would be close to nit picking. and everyone has to place there gear where it will fit in the room they have. most of which are not optimal. in your case, you don't have 2 side walls. so you gotta make due. if you get good size bookshelf speakers, put em here i say, i think you would be plenty happy with the sound. and they would be out of the way. for all but the most critical, rear/side placement has a good deal of flexibility.