my sub cuts out

[tennent]

when i turn my sub up a little not to loud but loud enough it seems to cut out and make the base come through the speakers again :S
it did the same in my old corsa and i didnt have a wiring kit + have a different one in this car.
i have tried a different headunit and amp so dont what it could be anyone had this before?

[Predator_R32]

Earth, how big of a wiring is it, 4 gauge 0 gauge?? and also where is it earthed??

Gain onm the amp set too high

Spec of the sub and amp etc??

[Killeybh]

i used to av it, you either need new thicker wires or a power cap