Um it actually looks like the way he has it wired up now he's only running one of the coils. He has the + from the amp going to the first coils + but then the - from the first coil going to the - on the amp. The second coil isn't actually connected to any power. He would need the negative on the first side to go to the positive on the second side. If you have it hooked up like that currently you may have damaged your sub. :/ At any rate don't play it any more till we get this sorted out. You are unevenly driving the sub if thats true. Anyone else look at that diagram and make sure I'm understanding it right?