I recently bought an A3 8L 1.6 in a priavte sale.
The previous owner has had a sony head unit fitted and told me they also fitted a signal booster whilst they were at it...whether there's any truth in that I'm not sure. The problem is the rear passenger side speaker.
When on mute there is no sound but when turned up the buzzing (not rattling like loose component) gets louder....
Any ideas will be welcomed.