Without knowing the exact make-up of your acoustical panels and without being able to hear the speakers themselves; I have a two thoughts...

First, I think your panels might be sucking out too much mids and highs without doing anything for the low range. Acoustical treatment can do amazing things when done properly. The problem is that it's a very fine line between proper and a result that you're not going to like. Controlling bass in the room is especially tricky.

Second, check the jumpers on the speakers. It almost sounds like there's an issue with the tweeters.

Hope that helps. Keep us posted.