Bayesian estimations of dissipation, sound speed, and microphone positions in impedance tubes

Abstract

Sound speed, microphone positions, and tube wall dissipation are critical parameters for absorption and impedance measurements using the transfer-function method in an impedance tube. This work applies a Bayesian method, based on a reflection coefficient model of an air layer and a boundary layer dissipation model, to estimate the values of these parameters for tube measurements. This estimation is based on experimental measurements obtained in the empty impedance tube with a rigid termination. Analysis results demonstrate that this method is able to accurately estimate the dissipation coefficient, the sound speed, and the microphone positions for highly accurate tube measurements.