How do you get it out of the housing?

 

Never mind, I figured that one out. I've done the searches so please don't flame me. I have a 5 month old so I don't get much time to myself. Rattling is much more improved, but more rattling is coming from the plastic piece behind the Bose sub towards the back window. When I push on it, almost all rattling goes away. What is under that plastic piece and how did you make it stop rattling?