New Rattle Source?

This would be covered by your warranty assuming you still have some of the 3/36 left.

Not sure why you would want to do it yourself.

 

somebody at the factory probably left a can in there.

 

It's not too tough to remove the panel.

1) behind the door handle (inside), there's a plastic piece that can be pried out carefully with a flat screwdriver. Then in the armrest, there's black piece of rubber just laying there. Lift it out.
2) You will see 2 screws (Phillips) that need to be removed.
3) Carefully lift up on the silver trim piece that surrounds the power window switch. It is held in place by plastic clips that fit into the door panel. Now lift up on the black power window escutcheon - it also is held down with clips. Disconnect the connector beneath it.
4) Now from the bottom of the door panel, find the place where your fingers can go behind it and gently but firmly pull away from that corner across the bottom and then up to release the plastic holders. Once they all "unsnap", lift up and away on the plastic door panel. Do not lose any of the plastic holders as they are just slip-fitted behind that panel.
5) The door handle assembly can be unsnapped from the panel from behind. This should free the panel - set it aside in a clean area. Allow the handle on its cables to drape or temporarily tape it to the clear plastic weather shield. Don't lose any parts

You might get a helper to drive while you listen in the back seat for the noise near the now exposed speaker.

Reverse the above procedure to re-assemble. Once the plastic holders are in place, press or tap until they all re-snap back into place.