Sound deadening
 

In my car, my subs give me a lot of rattling in the rear bumper area, instead of using something like dynamat, could I calm the rattling down with some polyfil?

highly doubt it, you could try something called liquid foam, read about it somewhere its supposed to help, but that was along with sound deading. If I were you I would just sound deaden it and get it over with. I did mine and it was not a big deal at all and it rediuced alot of rattles and road noises. I doubt you will little if any noise reduction with the poly-fil.

Polyfill, eh? That stuff is like cotton balls! Won't work for shit if you ask me. :rlaugh: Dynamat or "Brown Bread" (an inexpensive equivalent) would be better suited for dampening the rattling.

I checked b-quiet, and they don't sell brown bread anymore. What about this fatmat stuff on ebay?

Buy a couple cans of dynamat spray......Or The one MICRO electronics sells < i like to use that one............and its a lot cheaper

I would say use some undercoating spray in the tight areas then use some FatMat to kill the noise. Works real well for me and the 15".

i'll try to find this, but I don't know if one is in my area.

Don't forget the back of your license plate. Supposedly the license plate rattles alot in a high bass car.