From Physics I seem to remember that sound waves reverse phase every time they bounce off a hard surface. I've put on a signal generator for various frequencies and tracked results using a handheld sound pressure level meter to measure changes in volume as I've moved the speaker. My best guess is that the sound waves reenforce at some spots and frequencies and (try to) cancel at other frequencies at the same spot. how significant is this? Not very. All said and done, the direct radiation path is more significant than all other indirect paths in my small room. I don't argue; I just listen.
Why does pulling out main speakers from wall improve sound?
Ask my dealer this question and he was stumped. He said it's a good idea but couldn't say why. I see speakers pulled out eight or more feet from the wall in very nice systems.
The drivers are facing forward, and when there are no ports in the back of the speaker so why would it matter?