If I may suggest, try moving the speakers out into the room. They only excite those pesky room modes all the more the closer they are to where the modes build up the most: in the corners.
You do get a bass reinforsment, but it is not accurate. It is inscreased low frequency distortion, which in turn distorts the entire frequency range in the room.
Try listening to source material with refernce earphones (Shure E2 $100) and compare to what you hear in your room.