I’ve spent a lot of time and money putting in nice speakers and audio equipment in my 2009 forester. I also got all of the rattles and vibrations out of the interior except for the passenger side door. I’ve used sound dampening and checked everything I can, but somewhere on the door panel there is a vibration that I can’t find.
So, the only thing I can think of its too seal the various seams on the interior of the panel with something. … caulk or glass sealant?