RAAM Audio, best stuff out there (according to my friend who has been designing custom stereo systems for years). I think it's cheaper than dynamat too.

 

2nd vote for RAAM

 

I used e80 edead sound dampening.

I JUST finished today and I plan to take the truck out tomorrow to see how well it works in my truck. I covered a TON of random holes that served no purpose so I have high hopes. My friend installed on his 02 camaro and the drone is dramatically reduced compared to his sisters 02 with the same header/e-cutout setup. Before taking out the difference I've noticed is that when I close the door it makes a single "boom" instead of resonating clank sound.

The reason I went with edead is that it's only 2.00 per square foot with results like dynamat and if you google for a bit you will find a 20% off coupon that still works as of a few days ago. I got 80 sq feet for 167 shipped O.o! That's the same price you get 36 sq ft of dynamat.

I had fun doing it and I will post pictures tomorrow or the next day


Edit : I have a single cab f150 and I used about 75 sq ft using a single coat. I covered every inch of the interior + doors - Roof.

 

Where is everyone getting their sound deadening? Ebay only seems to have Dynamat.