LithiuMax

When my bass hits, there is a noise that comes from the left side of the trunk from behind the side marker (or around there). I peeled off the lining while I was sound dampening the trunk lid, and I saw a black box there which had little filter things in it and I think the noise was coming from the filters flapping around. It's almost like the sound you get when you put a baseball card into the bicycle wheel to make it sound like an exhaust.. any ideas on fixing this/what the black box thing is? Thanks.