VW installed some sound proofing in the doors and sides as well as the rear parcel shelf and the floor. The material was tar board but it deteriorated over the years and one has to re-apply something else when restoring the cars. The body shell of the Oval was meticulously cleaned before paint so it had to be sound proofed again after it returned from the painters. There is a choice of materials available but each has its advantages and disadvantages.
The material of choice is Dynamat but it is super expensive. I have been experimenting with a number of materials, some local, the others imported and I find Quick roof to be the best. I found it at Lowes in the US and at $18 a roll it is quite affordable (compared to about 3 times what Dynamat would cost) It is a peel and stick sheet with the non sticky side covered in aluminium. The product, as the name suggests, is for patching up roof joints and cracks but it works nicely in cars too. The best part is that it does not smell like bitumen even after the car has been parked in the sun.
I have started applying it to the insides of the door and will cover all the areas ..even those covered under carpet for a quieter cabin.
