Jonah, apparently there were two sources here for the ground loop hum; the more significant one came in through the cable TV connection and was eliminated with the Axiom cable TV isolator. Another was coming in by way of the subwoofer power cord and
this probably was the RadioShack item used to stop that. One of the cables would be plugged into the low-level sub input(or the receiver sub out, if more convenient)and the other side of the same color cable would be connected to the regular sub cable with a RCA coupler.
