SH- That's one thng I don't understand at all. The large number of speakers that are supposed to be used as surrounds and rears that are only rated to -3 dB at 80 Hz. That might work for a THX rated speaker where the speaker's roll off is purposefully combined with the crossover, but most people don't use a THX crossover setup with non-THX speakers. I even specifically asked Mirage about this with the OM-R2's, the speakers that are supposed to be used with what I have up front, and they either didn't understand the question, or pretended not to. So I went with their Omni 60's which are -3 dB to 45 Hz. And I even run that crossover a little high at 100 Hz, because 3 of the 4 are up against walls. The higher crossover helps deal with boundary low freq reinforcement.