Sound absorption property of carpet backing

Abstract

The characteristics on sound absorption which possess the peak of sound absorption coefficient in medium frequency zone and are often observed on carpets. We found that this characteristics were those peculiar to the carpets which had fiber assemblies such as fabrics, nonwoven fabrics and so on in the lowermost layer in the installed state. It was theoretically elucidated that this characteristics were on sound absorption, to which the resonance absorption of panel (membrane) oscillation type was added. In this case, as the parameters for the theoretical expression, if the mass of panel (membrane) was taken as the mass per unit area of the primary backing layer including pile part, and the thickness of air layer behind panel (membrane) was adopted as the thickness of the secondary backing layer composed of the fiber assemblies in the lowermost layer and underlay, the resonance frequency was in conformity with the measured value.