gene c
Senior HTF Member
I'm not the best to answer this but I'll try anyway. First, do you know the name and model number of the subwoofer and the amplitier? The rca connector (either A or B, your choice) would be hooked up to the receivers Subwoofer Out and the corresponding speaker output (again, A or B) would go to the passive subwoofer. I'm not sure why there are three wires in the cable coming from the passive sub.