I consider myself extremely fortunate that, in my listening room, I don't need any room treatments, nor do I think I need any. My living/listening room is connected to my dining room, which is connected to my kitchen. It measures 16.6" W X 34.6 D, with cathedral ceilings in the living room/dining room. The kitchen floor is uncovered, all else is carpeted.
I use two 12" Dual Concentric Stereo drivers, one 15" subwoofer, and two 12" subwoofers. Nothing is being overdriven (the nice thing about subs is they're volume is easily controlled). My room seems to have the right amount of clutter to help keep thing easier to adjust.
I also have a multi-channel system lashed in, and it has all worked out very well for me, which I am extremely grateful for.
Regards,
Dan