So about a month ago I finally installed subwoofer & amp to my golf IV with original speakers. Everything went smooth the first weeks, until one day while driving to work when my sub suddenly made a "pop" sound. After that the sub has never been the same, it just makes a low humming sound and an ocasionally pop whenever I turn it on or off or switch songs/radio channels. About a week after that my speakers started to make a couple of sparkling sounds, before they got this weird "whining" sound. Turning the volume down or up did nothing with it, it had the same volume no matter what. Turning it off and on again seemed to help for only a few minutes max then it would be back.
I've done A LOT of research on this subject without being successful, thus I'm making this thread.
What I've tried so far:
* Delivered my Kenwood 2-din player to the store which I got it from; They did some testing on it but found nothing wrong with it.
* Checked if my amplifier & sub works correctly; I connected the RCA cables directly from iPod to amp, and it worked just fine. I also connected the iPod to the RCA cables going from the amp to the front of the car, and it still worked fine.
* I've tried disconnecting the amp from the player, which led to my speakers not having the whining sound anymore.
* I've checked for loose ground connections, but they are solid.
One thing I got out of all my research was that I may have a problem called "ground loop", which some meant that you could ground your RCA cable to the deck of the player and it would work. However, this was for a slightly different problem called engine noise, where the speaker whining changed in phase with the gas pedal. I have not tried this.
One more thing that may be worth noting is that I have never completely attached the player to the car. It has been laying loosely inside the cabin, though it doesn't move much while I drive.
If you guys think you got any kind of solution to this, please let me know!! This has already taken too much of my time.