RE: [T3] Sound Deadening

["Jim Adney" <jadney@vwtype3.org>]

On 15 Mar 00, at 12:10, Jaranson, John (J.W.) wrote:

> The cheapest and easiest way to effect this is to add a heavy mat to the
> panel. This also raises the natural frequency of the panel making it less
> likely to be excited at the lower frequencies of the engine and road noise.

I agree that ribbing will stiffen panels and thus raise the resonant 
frequency, but I think that adding mass should lower it.

BTW, I don't think I said that you could dampen noise by just 
adding mass, I said that damping required mass (ie necessary, but 
not sufficient.) I was trying to kill the idea of a lightweight sound 
deadener. Yes, sound deadener requires more than just mass.

John raises a good point that a more effective way of controlling 
sound/noise is in the design stage where there may be little or no 
weight penalty. With an existing car, however, that is not an option.

-
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054

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