Actually what you do is hook up speaker cables to the receiver just as though you were going to run them to your right and left speakers. Instead you run them to speaker terminals (high level inputs) on the back of the sub. To do this, you must have a sub that has 2 pairs of speaker terminals, one for input, one for output (the red and black pairs on the back of this sub).
some subs do NOT have these, so keep that in mind when shopping for a sub. Then you run a set of speaker wires from the high level output pair on the sub to your right and left speakers. The adjustable crossover in the sub now separates the low frequencies and sends them to the sub, and passes the rest on to your right and left mains.
I've never tried Ken's suggestion, but it might be worth giving it a shot.
Well, assuming you've correct with the cubic footage, the EP 500 would certainly be advisable, if your wallet can stand it. It DOES have the high level inputs, but I don't see any hight level outputs. This would be something to talk over with the kind folks at Axiom. They are very nice to deal with, will not try to hype you into something you don't need, and will treat you wonderfully. They're interested in satisfied customers, not making a quick sale. Just explain you're doing a stereo hookup, with no "subwoofer output" from your receiver, but you want a sub. Give them an idea of your room sizes, and they'll help you. Honest, it'll be well worth the phone call.
