Just got a new subwoofer and need a bit of help connecting it to my PC. In order to connect the subwoofer, I'm going to use a cable that is 2x RCA on one end and 3.5mm stereo on the other. I know that the 3.5mm end goes in the orange slot on the back of my PC, but the back of my subwoofer has 2 sets of RCA slots. One set is labeled "input" and the other is labeled "output". Which of those sets of RCA slots am I supposed to connect to?