You need bass traps in the corners. I have some homemade ones using Corning 703, 4" thick, 18" wide and they remove exactly what you speak of. They actually impact the mids and highs much more noiticibly than the lows. Sometimes I remove them because I like the added airiness but I definitely can't turn the stereo up as much as I can with the traps.
I used to have the same problem with my TT so it is the room, not your CDs.
Arthur
I used to have the same problem with my TT so it is the room, not your CDs.
Arthur