Experimental study of the absorption characteristics of some porous fibrous materials

The sound absorption characteristics of a porous fibrous material, that is manufactured and used in Taiwan, is investigated. The flow resistivity and the absorption coefficient are the important parameters that are determined. The measured flow resistivity of the glass and rock wool samples were scattered in a wider range and usually greater than previously reported in the literature. This means that the manufacturing quality control needs further improvement. Additionally, the characteristic impedance of the porous material is estimated by the model of Allard et al and consequently the normal impedance and sound absorption coefficient is obtained.