Sub is acting funny

My JL 12" makes one hard hit after i take the keys out of my ignition... I believe this means theres a bad wire connection taking place? Look any place specific?

 

mine does this too. When i switch stations or change inputs it does that. I never tried to fix it but i think its a bad ground or something.

 

on/off pop? when i had my alpine headunit and audiocontrol epic four.1 eq in my 02...everything was gravy...i went an took out the old stuff in favor of a double din eclipse avn726e and didn't have room for my eq so i left it out and i was getting on/off pop on my sub. we tried everything from regrounding, new rca wire, resistors and nothing. even tried swaping 726e's. nothing. got sick and tired of it and last option was to add back the eq...well we did, and it worked. no more on/off pop.