Carl, I too checked the owners manual for this unit and could not believe my eyes. Unless this unit was a proprietary subwoofer for a complete speaker system that had a designated amplifier system. To use this unit with a normal receiver or amplifier, it would be mandatory for the equipment to be able to feed two sets of speakers at the same time. A large amount of older and newer receivers and amplifiers have feeds for only one set of speakers, McIntosh and Marantz for sure. I understand the owners query. What is he to do? [*-)] [*-)]