car stereo help

[Swift]

my sub makes a rumble noise when i change the tracks and makes a *thud* sound when the stereo turns on and off. i dont know wut happened. it started after i took my amp out and put it back in the next day. ive taken my amp out and put it back in a bunch of times b4 and never had this problem til now. anybody know wuts wrong?

[Sniper]

check the ground.....

[Swift]

i moved the ground to where my seatbelt bolt is and still has that sound. or is that still not good enough? it worked fine where i had the old ground tho so i dont know.

[NotAMonte86]

Did you move the ground the first time you took out the amp? Probably not... I guess check your ground connection at the amp. When you grounded it, did you strip away the paint? And the clearcoat?

[BOB]

Have you changed the location of where you are connecting to your power supply? That would be my first guess.

Other than that, I remember one of my Alpine amps had a circuit that subdued that turn on/off thump, perhaps yours had one and it is damaged? I'm stretching for that one.

[Swift]

i didnt move or change anything when i took out the amp. the grounds been in the same spot for months. yeah i sanded down that spot too.

[pstevens]

You want your ground short as possible and touch metal of the car not the bolt.... even sand it so it touches the metal of the car. Also keep your power wire away from your acc. wire or u will get bad sound. Make sure you + & - are right. Belive this or not it does make a differents.