somehow, i doubt you own or have used a DD-1. If for some reason i am wrong, and usually i am not, than you probably did not do it right. "ummm i left it at zero"...LOL what? Anyone that uses 0db tracks at the amplifier level shouldn't have any problem with overpowering their subwoofers if they are properly matched (in specs) to the amp they are hooked up to. Even though i don't believe you know what i am talking about, i just want to point that out in case somehow i am wrong. But i doubt it.
Yes I do own a DD 1, and the gains are set on point. When said set it on zero I meant I set my amp using the -0dB.