You don't hear about it enough--perhaps one of the best kept secrets. Try the Sunfire Architectural Sub. It's an 11" cube. Fast, tight, great extension and designed for two channel listening. Lists for $1400, but can be found, nicely discounted. I like the size and the way it integrates with my Revel M20s. I let my speakers run fully extended and crossover the sub at about 45 Hz. Beautiful. Good luck,
warren
warren