What have you used to deadenate sound?

[kurant045]

I originally posted this in the "modified Explorations section" but this is probably a better place to put it since a lot of people who are into good sound systems do this often. Here is my question.
I don't know about all of you but my truck rattles and squeeks with every bump on the road. I did a search for this topic in the forum and didn't find much info. I'm wondering if any of you have used different materials to reduce noise inside your truck. I want to get something that I can put under all my panels and maybe even the floor.
The only stuff I've heard of is something called dynomat but this is used more for perfecting audio and its quite expensive. Any tips would help. I guess what I want will help my sound system and also keep the rattling noise down when I hit the shaky 65mph on the highway.
please throw some opinions my way before I spend too much money.

Thanks in advance,

 

[Skippman]

This topic just came up here recently in the forum. Someone suggested using "roofing felt" and 3M double sticky tape. I have no idea how well this will work but I am extremely excited to find out. I'm going to do some research and possbily do this to my truck.