I have a Panasonic HT720 system in which all of the speaker cable and such comes out of the actual subwoofer. Because of this, there is no sub out on my DVD reciever, but there is a Line-out. I recently got a better home sub from a friend (its powered, so all it needs is audio input) but when i run the line-out from my reciever directly to the sub, it plays everything, not just the bass. Is there any way to seperate the bass channel from the line out so i can use this sub on this system? Or any other way to use it?