A filter representation of diffraction at infinite and finite wedges

Abstract

Diffraction of sound occurs at sound barriers, building and room corners in urban and indoor environments. Here, a unified parametric filter representation of the singly diffracted field at arbitrary wedges is suggested, connecting existing asymptotic and exact solutions in the framework of geometrical acoustics. Depending on the underlying asymptotic (high-frequency) solution, a combination of up to four half-order lowpass filters represents the diffracted field. Compact transfer function and impulse response expressions are proposed, providing errors below ±0.1 dB. To approximate the exact solution, a further asymptotic lowpass filter valid at low frequencies is suggested and combined with the high-frequency filter.