The output pre-amp is controlled by its volume knob. It feeds the crossover of the subwoofer which splits the signal and send the low pass signal to the subwoofer amp, and the high pass signal to the amp for the satellites. It works fine, and is a fairly standard "satellite-powered sub" set-up. The hookup is currently in place using "spare" equipment, like a Sony P9000ES analog multi-channel pre-amp from my HT/main system set-up as the pre-amp, and a Adcom 2535 /3/4 channel amp (normally for the rear speakers in the HT 5.1 set-up) powering the satellites. The satellites are Mirage Omnistats which hang nicely on the wall in my office and off the desk. (I've upgraded the parts in the Omnistats to make them sound a better -- WBT binding post (the old ones snapped with a heavy pair of spades!), Solen fast caps, Mills resistors, etc. -- they now sound cleaner, more dynamic, and spacious) They are wired with AlphaCore Goertz MI-2 which snakes up nice and flat behind a shelf, besides sounding pretty good. The 9" cube Sunfire Jr. sub fits great and is incredible for its size. Now I need to get the Sony off the desk (replace with a passive?), and replace the Adcom (with tubes, I'm thinking, but I wondering how the passive pre -- crossover/sub -- amp interactions and compatibility will work out, and how to optimize it). Now let's see, maybe Kora Galaxy, SF Power 1, Rogue 88 Magnum, something from Blue Circle??