I have two 12" JBL LC - S1200w's. One doesnt make any sound what so ever and the back part of it where you can hold the magnet, the hole where the paper is at or what ever that is, is blown. The other sub sounds like it has rocks in side the part where it says jbl that sticks on on the subwoofer. So every time you play or shake it you hear rocks moving around, very annoying. The dip shits at custom sounds told me the amp would be perfect for them and that there mono subs, but there 2 channel cause there not bridged togotor or what ever.