Re: Brass freight car noise


Schuyler Larrabee
 

As might a stick of styrene carefully wedged between the sides, perhaps glued in place.  CAREFULLY as you don’t want to inadvertently deform the car sides by pushing them outward so make the stick just long enough to stay in place but without using a lot of force.  By changing the length of the vibrating side, you interfere with whatever resonance is causing the noise.

 

Schuyler

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Dennis Storzek
Sent: Thursday, August 27, 2020 11:20 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Brass freight car noise

 

On Wed, Aug 26, 2020 at 07:38 PM, erieblt2 wrote:

Working with sound isolation for the Navy the noise-vibration-can be lessened by of of two (or both) methods: isolation or increase mass to change the vibration (Noise)wavelengths.

Indeed. The hollow brass body is acting as a sounding board, amplifying the vibrations caused by the wheels on the rails, the same as the hollow body of a stringed instrument amplifies the vibrations of the strings. What is needed is to change the resonance of the body. If the model could use a bit more weight, I bet a couple of those self stick tire weights that some use for weighting cars would help, IF they were stuck to the inside of the body shell rather than the floor.

Dennis Storzek

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