Hey, I am having kind of the same problem. So far i have found that you need a hi/low converter. Unless you have RCA-out jacks on the back of your receiver, which you probably dont. I have also read that you can skil the hi/low converter if your amp accepts high voltage input? whatever that means. I hope that gives you something to work with.
I also wanted to ask, on the same topic. When using a hi/low converter, i just want to power one sub, and there are 4 wires that i have to splice into my system. What wires do i splice them with, and is there any way to make the converter work as a mono....my sub is single coil and i am using a bridged amp.