Date:         Tue, 19 Oct 2004 08:57:53 -0700
Reply-To:     Randy Bergum <organslave@EARTHLINK.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Randy Bergum <organslave@EARTHLINK.NET>
Subject:      Re: noise reduction
Content-type: text/plain; charset=US-ASCII

My Audi A4 has removable plastic inserts in the wheel wells with a sort of
fuzz on them - and that car is pretty quiet.  These covers can be removed
with Dzus-like fasteners to access the innards of the car - all kinds of
stuff is crammed in every little bit of space around the fenders.  I
suspect that the pliable nature of the plastic combined with the sound
impedence mismatch to the metal car body gives a good quieting effect.
        Here in Orange County, CA  some freeways are using an asphalt mix with
some rubber in it - These roads are noticably quieter.  So everyone lobby
their congressman to replace all the roads in the country!

Randy Bergum
1990 Carat


> [Original Message]
> From: Kim Brennan <kimbrennan@MAC.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Date: 10/18/2004 10:48:16 PM
> Subject: Re: noise reduction
>
> Modern cars, and especially luxury cars have a very quiet ride. They
> also have a lot of noise deadening materials between the outside and
> the inside...
>
> Vanagons, by their very design don't have as much space in the doors
> (for instance) as my Jaguar Vanden Plas. That limits how much deadening
> material you can put in the door. Dynamat, B-Quiet, and BrownBread are
> very thin materials,l whose primary purpose is to reduce the resonance
> of the surface they are placed on...usually the sheet metal of the
> vehicle. Other materials are needed to reduce the noise that pentrates
> that is not due to resonance. Tire noise is one thing. Different tires
> have different amounts of noise. Tire manufacturers spend a lot of time
> redesigning their treads for the purpose of canceling out the noise the
> tread generates on pavement. Mostly, they do a remarkable job.
>
> However, the noise from the tires isn't coming (primarly) through your
> doors. it's coming from underneath the vehicle, so if you aren't
> dealing with blanking the noise from down below, you won't be silencing
> your vehicle. That means the tire wells...and the area underneath the
> front seats. In the back its the area right behind the rear seat.
>
> The other two major sources of noise are wind noise and engine noise.
> At highway speeds, the wind is hitting the front of your van. That
> means you have to have noise deadening material up front, like in front
> of your dash. One of those projects that will require pulling the
> dash...
>
> Engine noise comes from the back. In my passenger van  there is some
> soft of asphalt like material on the top side of the engine compartment
> (which has been painted over). Probably something similar to one of the
> above products. However, without some additional sound proofing
> material, there isn't much else insulating the engine noise from the
> main compartment.
>
> Of course, I have an advantage in that I have Syncros. Syncros have the
> gas tank in the back, and that provides quite a bit of buffer above the
> transmission, leaving the only the area on top of the engine has
> needing sound proofing.