Don't you have a manual? I just did a search on Google and found this...

"Subwoofer Direct input This input bypasses the CHT Subs' internal crossover to provide direct connection to a preamp-level subwoofer or LFE output. This exclusive feature assures the highest levels of performance and compatibility with all digital surround processors, now and in the future."

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85