the other thing you might want to try is angling the speakers at 45 deg instead of having them straight out from the rear wall. I have done that to reduce room reflections and standing waves. Works well in my small room. Moving them out from the rear wall, as others have stated, does improve imaging for sure, and rear wall reflections.
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?