Posted by: "Klas Strandberg"
> I will ask at a nearby industry if they can make me a small box out
> of concrete. Or perhaps put sand bags over the mic? (I'll bet there
> are ants making noise in the sand...)
From experience with electron microscopes, concrete by itself is not
necessarily going to limit vibration transmission. When I was in
university we could tell the vibrations of folks walking past the
massive concrete building the microscopes were in. Transmitted through
lots of concrete. Critical work was done in the dead of night. When a
new building was built the vibration isolation of the electron
microscopes involved not only large masses of concrete and steel, but
layers of vibration suppression in between. The electron microscope room
was built in several isolated layers. Made the biology building a lot
more expensive.
And you don't want to get into the fun of cutting thin sections to look
at under those microscopes. Not only vibration suppression, but precise
thermal regulation were necessary. After many hours of failure, the
sections would start to come off right and you'd get excited and lean
just a few mm closer to the machinery. And ruin things when your body
heat changed the thermal expansion of the equipment.
Anyway, layers of dead air are the key to sound isolation.
Walt
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