PROPAGATION FROM A POINT-SOURCE OVER A ROUGH FINITE IMPEDANCE BOUNDARY

Measurements of the excess attenuation of sound from a point source ov er artificially rough surfaces in an anechoic chamber are compared wit h predictions from modified forms of theories by Howe [J. Sound Vib. 9 8, 83-94 (1985)] and by Tolstoy [J. Acoust. Sec. Am. 72, 960-072 (1982 )]. The modified theories agree with each other and are in tolerable a greement with data over hard or nearly hard boundaries. The modified T olstoy formulation, which allows the roughnesses to have an impedance that differs from the impedance of the surrounding plane, is found to give better agreement with data for propagation over rough finite impe dance surfaces. (C) 1995 American Institute of Physics.