Obviously I can't set up the rear speakers on the either side of my head. My only option is to put the rear speakers in the back. Is that gonna cause a noticeable difference in the sound quality/effects?
I can always return the speakers if the setup in my room is no recommended.
The only thing to make sure of, is that the distance regarding the rear speakers from your couch are the same. Dont make one 5 ft away, and the other 3.5 ft away. That will mess with the sound. Otherwise, it should work just fine.
just make sure that you set up the rear speakers at the same distance from the point at which you sit. SO, that means, if one speaker is 3 ft away, the other must be 3 ft away. Same goes for the front speakers (independantly from the rear), just make sure that the front 2 speakers are the same distance away from you.