I just bought a used Pioneer vsx-7500s audio/video stereo receiver. I am trying to connect an RCA subwoofer to it but there is no subwoofer input in the back. The subwoofer has the option to use the black and red wires (hi-level input.. output) or a low level input wire... on the receiver I have an open CONTROL IN and OUT and a A CENTER AMP PRE OUT... could i use either of those or should I use the black and read component wires and hook up to speaker inputs