Panelhead

I have a problem with intermittant alternator whine the stereo. Have checked everything connected to the stereo. Even added grounds to remove.
The issue occurs after hitting a bump. It goes away after hitting another bump. It is worse in dry weather. Rainy weather there is almost no problem. It sometimes only last a minute, other times an hour.
I have looked in my manual and under car to see if there is a ground cable running from block or alternator that may be corroded. Cannot find it.
The car spent the first 8 years in NYC and Long Island. It has had exposure to ice melting chemicals. maybe some salt water from the hurricane there too. Here in Houston we get ice every 3 - 4 years and the weather melts it in hours.
Anyone here experience alternator whine through the stereo? The vibration trigger sure seems like a mechanical ground issue.

Jehu8

Do you have any aftermarket devices like a built in radar? Do you have a Aftermarket Amp for the Sub? Try disconnecting the Amp If any and see if it comes back. Did you check the trunk battery for loose connections? I know there Is at least one Earth ground (ground welded into the chassis) near the battery, not sure for the other side where navigation is kept. Love the A8's look by the way.

Ninja Edit: Also because you have aftermarket speakers ,each speaker is a potential culprit