I have a 600 sqft HT with a 13ft diag screen, sound comes through JBL speakers set up as a normal 5.1 system. I am thinking of going to 6.1 or 7.1 set up with speaker(s) either in the wall behind the sitting area or surface mounted behind which is how I have the other speakers set up. The...

My room is currently setup as a 5.1 setup but my receiver can be setup for 7.1 surround. I'm wondering if I would get much benefit adding two more surrounds. I would think that room size would have a lot to do with it. My room is 13" X 15" but open on one side.