I have three subs in a room smaller than 13x17 and they work fine. I used soundhounds stereo sub idea and then added another for the LFE. Adjusted the volume of each so they are not overpowering and cut all at 80Hz and below. In this setup, I have bass that is tight and clean and you do notice it move with the action of the movies. Highly recommend. You may have your subs set too high, tone them down to match the level of the rest of the system.