A PRELIMINARY REPORT ON MEASUREMENTS OF SOUND ABSORPTION COEFFICIENTS OF CHINESE ACOUSTICAL MATERIALS
国产吸声材料的吸声系数测定的初步报告

Normal sound absorption coefficients of some Chinese acoustical materials as measured by the tube method were tabulated and problem of conversion to random coefficients was discussed. Our results: most of the prefabricated units showed low absorption efficiency especially at low frequencies.In order to clarify the feasibility of these acoustical materials and to throw some light on the development of our future acoustical material industry, test data and relevant theoretical interpretations were presented for the effects of paint, thickness, flow resistance, and perforations etc. on absorption characteristics, and also for the functions of panel and perforated-panel absorbers. Emphasis was made for the last type for its versatile acoustical applications and insufficient use in this country. A conclusion was drawn with several suggestions both for the improvement of the existing products and for the manufacture of new ones.