I havent tried our theater in 5.1 but the side rear's are placed a bit in front of the listener, at about 6.5 feet high. Im sure we could have gotten away with 5.1 easily but its not everyday I get to design a dedicated theater so 7.1 it was since the back rears are behind us it really does give the effect of things flying over your head and stuff. Even though most movies barely make use of the surround channels

Haoleb's Audio/DIY Website