After watching a bunch of movies I can safely say the center channel is interacting with the AT screen audibly. I think the screen isn't an issue for db drop or frequency filtering so much, but creates a parallel surface to the front wall creating a very weak boxy sounding echo. I would describe the sound as someone talking to you then cupping their hands around their face (not just mouth) and talking. Subtle but noticeable. I might just be hearing the difference of its response at ear height, instead of below the screen as I was accustomed to. I might try to put something behind the center channel temporarily and see if the effect is negated.