I have preamps on my JVC headunit for 'front channel', 'rear surround', 'subwoofer', and 'center'. The front and rear channels are both red and white pairs, but the subwoofer preamp is a single blue coax, and the center preamp is a single red coax. I have the sub hooked up to the front pair, but I'd like to know how to hook it up to the subwoofer preamp so I can control the sub volume. How do I do this? Do I hook the white to the blue subwoofer coax and the red to the red center coax? Thanks in advance.