buzzing and rattling in the trunk

I recently installed a pair a 12''Kickers bridged to my 1600w amp in my trunk and have been gettingf great sound and bass. exept for the loud rattling sounds i get. its really annoying from outside the car bbut not so noticable from the incide. I know its comin from the top of the trunk but im not sure what to do to git rid of it.

If i put down dampining sheets will it help get rid of the rattle? but not take away any bass? Or does any1 got any other ideas or advice?     

a dampening sheet has nothing to do with bass and everything to do with resonation.  When bass contacts a flimsy surface, the surface flexes in and out, just like the speaker that reproduced the bass.   When panels in your car resonate, they are absorbing the bass waves, this means less bass, so in fact as small scale as it may be, sound dampening increases your bass. This resonation is also what is moving whatever happens to be rattling in your trunk. Although i dont think dampening will help much it is a start, the key to getting rids of your rattles is usually a good tightening of things in your car.  You need to tighten everythin in the area of rattles, like a spoiler, tail lights, back deck, third brake light, trunk lid, even bumper.  That should fix your problem..... i once had a car that i could not silence for the longest time, i found out it was the gas tank rattling in the straps.

Bass sucks.......but we all deal with it.