TSi Series speakers sound best when used with a quality subwoofer, such as the PSW Series from Polk. PSW125 and PSW110 feature matching wood grain to all TSi speakers. Use the larger and more powerful PSW125 to round out the ".1" of your system. If you don't need quite as much thump, the PSW110 is a little smaller and affordable. For better results, use two of the same model. If the PSW125 or PSW110 is too large for your needs, the PSW111 is the perfect solution. Occupying less than a cubic foot, it fills in the lows without filling your room.