ACOUSTIC PROPERTIES OF PERMEABLE MEMBRANES

Membranes used for building materials have a certain degree of acousti c permeability, which has been disregarded in general membrane-vibrati on theory, and may cause serious effects especially on the acoustic pr operties. In this study, a theory for sound absorption of, and sound t ransmission through, a single permeable membrane is developed. Subsequ ently, sound absorption of structures composed of air layers, absorpti ve layers, and the facings of permeable membranes is investigated theo retically, and discussed in comparison with the experimental data meas ured by using the reverberation-room method. The results are in fairly good agreement; thus the present theory should give an effective tool for prediction of the acoustic properties of this type of membrane st ructure. (C) 1996 Acoustical Society of America.