I've used several kinds of sound dampening over the years in various
vehicles but just stumbled over something that could be the best, in
walls/doors.  My Westy has FatMat or similar from the PO and even though he
installed too much I had to add more last year just to make it useful in
the doors.

Yesterday I decided to cover my Small Car ABS skins with Van Specialties
interweave fabric and 1/8" foam.  3M's Super 77 works great for both.
After installing it I noticed a thud.  Again later.  By nightfall I
realized the doors sound MUCH better than any doors soundproofed with ANY
thing I've ever used.

They didn't sound bad before but now I intend to experiment with the foam
more and see what develops.  It's just typical, yellow, closed cell (?)
foam they use when converting Sprinter walls and trim.  I don't have a
snazzy website to show and tell but thought those more progressive owners
here may want to try it too!

--
Neil2
'82 Diesel Westfalia (Ducky)
'86 Vanagon/Westfalia Wannabe (SaVannah)
'08 170" 2500 Mega Roof Dodge Sprinter (Moby)
'90 Westfalia Subagon
Fulltiming since August 2008
Nunquam Pendite Divendium