Jim Salk has speaker models into which he installs a Rythmik Servo-Feedback 12" or 15" sub, and he also builds custom cabinets for Rythmik subs. I would imagine any Salk speaker would benefit from a pair (two is always better then one, no matter the size of the room. In fact, the smaller the room, the more of a benefit is the second) of Rythmiks. Head over to the Rythmik site, and check them out. You can get a pair of 12"ers for $1200, I believe.
