why does it thump?

[GiganticPrune 10+ year member]

so i get a loud thump when i turn on and off my car from my subs.

at first i thought it was a poor ground of some sort, but i switched from my eclipse cd5000 to a cd7000 (using the same wiring harness) and i had no thump..when i switched back..i have thump again.

what gives?

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[Etac 10+ year member]

i have the same problem ever since i added my external eq..i've basically tried everything and nothing fixes it..whatever.. it doesnt seem to hurt anything and try turning the radio off before you shut off the car and turning it on after the car starts should stop it, but i know thats kind of a fake fix

 

[Phlipbak 10+ year member]

Ya this is the subs popping because the headunit cuts on after the amp is cut on. You can put a delay in the line and it will fix this. Same concept as if you had studio monitors and cut on the interface after the speaker were cut on. It's an initial signal sent out by the power being cut on.