I had an addition built and the contractor pre-wired the room for 5.1 sound. He ran wire for the subwoofer (black and red) and used a push type RCA connector for the face plate. Apparently he cut off an RCA pin and soldered the black and red wired to the back of the pin. The wire have since come off. Is there anything I can use better than soldering the wires to the back? Do I run the risk of having polarity problems? What do you recommend? :confused: