The state of the art in measurement and characterization of scattered sound.

Abstract

For over 100 years, the acoustical industry has measured and characterized sound absorption. And yet, standard measurements of the random incidence absorption coefficient, according to ISO 354 and ASTM C423‐09, still do not provide an accurate answer. Nevertheless, acousticians utilize this inaccurate material property in several formulas, including Sabine, Norris–Eyring, etc., to predict a room property called the reverberation time. All measurements and predictions rely on the concept of a diffuse sound field, which is yet to be fully characterized in the standards. The field of measuring and characterizing scattered sound is in its infancy by comparison, yet in the past 3 decades much progress has been made. Two standards have emerged for measuring scattering (ISO 17497‐1) and diffusion (ISO‐17497‐2) and the current state of the art for both will be reviewed. While much progress has been made in measuring and characterizing scattering surfaces, we still need to develop a relationship between these mate...