I bought a Yamaha RX-V620 5.1 home audio receiver. Later on, I then bought a Toshiba speaker system which came with 2 mains, a center, to rears, and a subwoofer. I have successfully hooked up the speakers, and they sound great. However, the only output jack for a subwoofer available on the receiver is some sort of single jack like maybe a coaxial speaker cable or something. However, my subwoofer doesn't not connect this way. It connects to a amplifier/receiver through the red and black (negative and positive) cables. How am I supposed to hook my subwoofer up if there's only a single coaxial jack for the wub on the amp by my sub hooks up with the neg/pos cables?