Might be a dumb question, but I don't want to put a subwoofer in my car (as in with the amp and new deck, and I know this is about a car, but its audio), but one I could hook up to a an AUX Cord as I have one. So is there a subwoofer with an amp or similar already wired to it that I could simply split the connection from my iPod to the cars speakers and then to the subwoofer and hook up external power? If this all makes sense?