popping sound on start up and shut down

I installed a parrot 8400 h/u along with a rockford fosgate 400.4 amp, 6.5s and a 10'' punch sub all in a 62 corvette. After you turn on the key but before the radio starts playing I get a popping sound, and after the key is switched off i get another loud pop a few seconds after everything shuts off. I tried running a new ground straight to the battery and a new set of rcas but the noise persists. suggestions?

edit: got it figuered out. it was the parrot deck. tried another parrot, same problem, tried a pioneer and all is good.