Noise dampening due to a vibration source

[irenaw]

Hi

Assuming a small disk (say, diameter of 10 mm, width of 3 mm) is vibrating at a certain frequency in air, producing sound. Assume the first version of such disk is made out of steel, and a second version is made out of a soft material like sponge or hollow rubber. Will the softer material produce less sound? Or are they about the same?

Thanks

 

[IRstuff]

Probably pretty similar, for the audible frequencies and sound levels. Most speaker cones are made from relatively soft or flexible materials.

TTFN
faq731-376

 

[Tmoose]

hollow rubber = open celled foam? But "vibrating" with just the same amplitude as the steel disk?

 

[GregLocock]

Depends on the frequency, amplitude, and material properties of the diaphragms, and their dimensions.

At sufficiently low frequency they will be similar.

Keywords for your literature search are "radiation efficiency" "Coincidence speed" "critical frequency"


Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?