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Fiber porous materials, such as
polyester fiber sound-absorbing cotton (cotton insulation), wave
absorbing sponge, Pyramid absorbing sponge, absorbing material
has a large number of internal
mechanism is small connected pores, these pores can penetrate
into the acoustic wave along the
sound-absorbing material, and sound-absorbing material occurs
friction energy will be transformed
into heat. The absorption property of porous sound-absorbing
material is gradually increased with
the increase of sound absorption coefficient frequency, which
means that the low frequency
absorption of high frequency absorption is not good.
Undefined
The necessary conditions of porous sound-absorbing material:
material has a large number of gaps,
the gap between the internal pore materials deeply connected
with each other. One of the mistakes
is that the surface roughness of the material has a sound
absorbing performance, in fact, for
example, stucco surface concave convex stone does not have the
basic ability of sound absorption.
The two is that the wrong understanding of material has a large
number of internal holes of
materials, such as polystyrene, polyethylene, obturator
polyurethane, sound-absorbing performance
is good, in fact, these materials due to internal holes no
connectivity, not deep inside the
material acoustic vibration friction, so the sound absorption
coefficient is very small.
This will remind you not to mistakenly believe that the material
has a large number of gaps or a
large number of empty holes can play the effect of absorption
done otherwise a soundproof treatment
had no effect but also remove trouble..
.