I'm a fairly new to wiring car audio systems but, I have experience wiring a lot of other car electrical systems... Anyway, I wired my 4 12" CVR DVC 4 ohm in parallel to get a final 2 ohm load to my zx1000.1. However, only the second and fourth subwoofer worked; any ideas on what's wrong? I know all four subs worked because, I tested them out in the summer. I believe they were wired in series before; any help appreciated. Thanks.