I haven't found much discussion in the forums about the THX box on the bass management page in Mconfig.

First, does anyone know of any official THX Ultra 2 approved subs? According to M this means it's flat to 20Hz. Most subs (even very good ones) would not fall into this category without equalization of some type.

Also, if you check off your sub as being THX Ultra 2 approved, an option for Boundary Gain Compensation becomes available. The owners manual says very little about this except that it's meant "to reduce bass levels if listeners are close to wall". Does anyone know anything more about what exactly Boundary Gain Compensation does? Is anyone using it with noticable results?