No.2（1999）12.Sound absorption coefficient of three dimensional fabric

Masataka SAMITSU, Kokichi KATO and Takashi IMAI

Three dimensional fabric with a cross section structure similar to corrugated fiberboard was developed. The relation between the structure of this fabric, type of thread, thickness of the fabric, mass per unit area, permeability and back air space and sound absorption coefficient was investigated. As a result, the size of the back air space greatly influenced the frequency characteristics of the absorption coefficient. Also, the permeability of the fabric influenced the absorption coefficient, when there was back air space, and the permeability and thickness of the fabric influenced the absorption coefficient, when there was no back air space. In order to increase the absorption coefficient of this fabric further, these are effective when the permeability is 30cm/s or less and the thickness on the fabric is increased.

Keywords
Three dimensional fabric, Air permeabillity, Sound absorption coefficient, Reverberation room, Sound absorbing material, Normal incident, Back air space

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