The brain can judge distance from sound specifically its reflections, speakers close to a wall create reflections very close in the time domain to the original sound this means your brain 'knows' this is a small space. Speakers further in the room have a longer delay thus the brain hears a bigger space.
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?