No doubt about it: The TacT 2.2XP! The Rives is an excellent PASSIVE unit, that will bring down peaks, but can do nothing about nulls. The TacT allows one to place the actives woofer of one's bi-amped system in the corners of the room where they can effectively load the room evenly and aligns them with the main speakers in the time domain. It also provides the option of a parametric EQ, if you want to curve the room via a steady-state(pink noise) signal in addition to the unit's automatic Fast Fourier Transform fuction(among a number of other features). If you are not thinking of actively bi-amping your system, the Tact RCS 2.0 preamp is what you'll want to investigate.