ok i haven't been driving my car all winter, but i had to give back the car i was borowing so i am driving my car again. the other day i was driving around and out of nowhere the sub cuts out. i didn't have it pounding and it wasn't that cold. right around 0. so i turned it down and you could hear the sub a little at low volumes but as soon as you turn the volume up to a normal listening level it cuts out again. the amp comes on and stays on so it is not that. i am guessing it is the sub but i am wondering what could of caused it to go without really pounding it. oh yah, the amp is a Zappco AG 750 and the sub is a quad 1ohm 18" inhuman.

Sounds like possibly a short in the speaker wires, too low of an impedance, or a bad coil(s).

With the temp around freezing you may have a good buildup of condensation on the equipment. It may cause a short.

It has happened to me in the past. Something to watch for.