Or any battery.....9v battery will work also
Should slam, not sure what's going on.they are in phase. according to the battery test
what amp are you even runningim pretty sure they are all in phase, 2 ohms and they should be getting 325 rms per sub (rated at 300 rms)
they are rated at 300 rmsOnly a 2kw amp on 4 15's ? I'm running 3kw on 2 12's ...