Sub making Popping Sounds

My 12" sub makes constant popping sounds its a consistant pop it also pops about 5 times after I shut off my truck. its a 1500 w sub with a 780 w amp. subs is dual vc wired parallel. The rest of the wires are correct to as far as i can tell. Any help? Thanks.

make sure the gound is grounded to metel chassis. Not through paint. also make sure the RCA's are connected properly.

Sounds like it's either a bad amp or incorrectly wired. It should never make any noises after you shut it off.