Im looking into sound deadening/dampening the interior of my car. Dynamat is probably the best known companies to make this material for car audio. However, I have noticed that there is a lot of other companies that make this material and sell it for less. Also there are some products that can be found at local stores like Home Depot or Lowes that are used on roofs that are very similar(if not identical) to Dynamat. There is something called Peel and Seal that I went out looking for today that was supposed to be good and costs a lot less (Didnt find it). This stuff is used for sealing up roofs on aluminum sheds and mobile homes. If anybody has input on some of the other sound dampening materials, let me know.