I'm looking to set up a 5.1 environment...however, I live in an apartment, and my sofa is against the rear wall. Whats the best way to mount a pair of QS4's in this scenario, without having to move the sofa off the wall?

There's about 1.5 feet of space on the sides of each end of the sofa before a side wall...I was curious as to whether I should get the Axiom mounts and put them in the corners, on the side wall, or on the rear wall.