I once had a fireplace in the middle behind my speakers with glass doors on the enclosure - - it did great damage to the soundstage due to first reflection point issues. Absorption worked for me then for dedicated listening sessions (but really did not work for my SO!). Now in a dedicated room I have a wall with GIK panels behind the speakers and I enjoy a deep and expansive sound space. Maybe deflection would work even better, but I love my art panels - - much more interesting to look at for me! I also employ absorption at the side wall, ceiling, and floor first reflection points.
Sound Absorption Behind and Between the Speakers?
Recently my system moved to a new listening room and I was not enjoying the sound very much. There is a window between and behind the speakers. Last night, I put three sound absorbing panels right in front of the window and added a couple salt lamps which illuminate the panels. The sound instantly became way better! I have a soundstage now! I am not sure why though. Do the absorbing panels really have that much of an effect? Or does the fact that I added the panels with the salt lamps give my mind a surface to project the soundstage on which makes a bigger difference? Bit of both?