I think Alvin hit the nail on the head. There are two types of material we can ues in our turcks. SOUND DEADENING and INSULATION. Both will reduce the noise in the cab, but I think each has it own advantages.
SOUND DEADENING material such as Peel & seal or Dynamat are basicly a thin >1/8" asphaltic material with a aluminum facing. This is used to reduce the "ringing" of the metal body. It will give your a nice solid thud sound when you close them, and your cab won't sound like riding around in an old tool box.
INSULATION material is typicaly a thick fiberous pad that you would use under the carpet or headliner to cut down on heat and noise transmission. I'm not sure of any specific brand names but some look like shredded carpet fibers bonded to an aluminum facing, others look more like a thick piece of felt.
I think if you use these two types of products you can achieve a relative quite and comfortable ride.
Here is what I did on my truck just for reference. I installed the Peel & Seal as a sound deadener on the inside of the entire cab, (walls, floor, roof, firewall, even under the dash). I also covered the inside of the doors and door panels, (easy to do on my 46, not so on AD's).
Then I used sone foil backed insulation, which came from Home Depot, sold as an insulation blanket for a water heater, and glued it to the roof and back wall of the cab. All of this was covered with the headliner or interior panels behind the seat. I didn't use this in the doors because I was afraid it would soak up any water that may get into the door from the windows and cause a rust problem. Then under the carpet is a thick felt like padding that was installed by my upholstery guy.
The final product is solid sounding doors and a fairly quite interior.
I hope this helps.
George
