Acoustic properties of permeable membranes

Membranes used for building materials have a certain degree of acoustic permeability, which has been disregarded in general membrane-vibration theory, and may cause serious effects especially on the acoustic properties. In this study, a theory for sound absorption of, and sound transmission through, a single permeable membrane is developed. Subsequently, sound absorption of structures composed of air layers, absorptive layers, and the facings of permeable membranes is investigated theoretically, and discussed in comparison with the experimental data measured 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 structure. (C) 1996 Acoustical Society of America.