Thumping noise from subwoofer output

[4xGmc 10+ year member]

Ok I tried grounding the rca's it helped some but it was still there also it only does it while playing a cd and it doesnt do it with any other outputs just the sub out and the player is only 2 months old

 

[naiku 10+ year member]

Ok I tried grounding the rca's it helped some but it was still there also it only does it while playing a cd and it doesnt do it with any other outputs just the sub out and the player is only 2 months old

I have a similar problem, I get a thump from my sub when I change source/station but not when changing CD tracks. I already grounded my RCA's, and have my HU grounded directly to the battery, next I plan to try re-grounding my amp, and then grounding my HU and amp to the same spot.

If none of that works then I am stuck. I keep thinking I should not have bought the Pioneer I have but a used older Alpine instead.