Dynamat, Cosmopolitan Motors

[RonHorowitz <RonHorowitz@domain.elided>]

>I'm thinking of adding some dynamat or similar sound absorbtion material

Picking at nits, but Dynamat (or at least the product I'm familiar with)
isn't sound absorber, it's dampener and mass.

> there was a less, expensive

Anything from asphalted roofing paper to used chewing gum would skyrocket
in price if given a well marketed brand name and sold by car stereo jerks.
Regardless, sound absorption isn't a product, it's a process. A less
expensive method? Go to the library and check out Leo Beranek, Harry Olsen,
et al. Not the answer you were looking for, I suppose, but my best advice.

>and lighter alternative.

For STC, double or tripple mass layers suspended between light, compliant
layers work better than single layer mass. For eliminating panel modes,
rolling stiffening ribs into the panel weighs nothing. Determining the
transmission paths and the mode shapes, and then determining what best to
do about them is the $100 an hour question.

>I don't have an opinion of Cosmo Motors,

FWIW, I can state the following as fact. I have a friend who bought a car
from CM. A number of statements or claims made by CM were proven to be
factually incorrect. Thousands of dollars worth of grief and legal fees
later, CM was ordered to buy the car back again. YMMV, but a used car
dealer is a used car dealer.

RON
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