Speaker buzzing/ screeching?

[docbrown2015]

I got up this morning and unlocked my doors to get into my 2011 Z4 and the left speaker behind my seat was making a loud buzzing screeching sound, even while my engine was completely off. I started the engine through my radio and CD player and I couldn't hear my gong come on because the buzzing was so loud from that one speaker, I was sitting in my car and then turn the engine off and the buzzing was still persisting, so I got out of my car and locked the door for about 30 minutes and open my door and the buzzing stopped and the speaker is working fine. is there any idea of what this could be?

 

[AnubisZed]

Strange one that :|

Do you have the multi-speaker package (12 or 14) or the standard package (6)?
Asking as the multi package is fed through an amplifier so there's the possibility of a potential induced feed. This "could" mean you may have a fault with the amplifier, but I'm just guessing here. If you only have the standard package then I don't see how as there are a lot less components here, but again this could still be an induced feed and so could potentially mean the headunit is at fault (amplifier is built-in here).

I don't see it is something you're going to be able to rectify easily, but will just have to monitor and see how it goes over time.

 

[buzyg]

That sounds like and earth in the system some where. Have a read through this thread. It may help. https://www.1addicts.com/forums/showthread.php?t=319049