I want to attach an sub to a Panasonic SC-AK 410 shelf sytem and i was wondering how to put power to the sub and sound at the same time???? I have an adapter for in the house and it has a 12 volt thing on it that i can change it to. and when i put just that on the sub theres a low humming sound but if i put just sound from my shelf system i hear music but just not a lot of it and i was wondering if you can put the power from the adapter and the sound from the stereo onto the sub using only two conections(that are on the sub)????