Characterization of the propagation coefficient and characteristic impedance in an extended frequency range

Characteristic impedance and propagation coefficient are two critical parameters in acoustical material research. This work uses Bayesian inference to explore the performance of characteristic impedance models at high frequencies. The characteristic impedance and propagation coefficient are measured using the three-mic method [Salissou & Panneton, J. Acoust. Soc. Am. 128, pp. 2868–2876 (2010)]. To extend the frequency range, multiple microphone measurements are averaged. The empty impedance tube measurement with a hypothetical air layer enables the validation of the extended-range characterization. The critical parameters in characteristic impedance models are estimated using Bayesian inference. Porous materials are used to compare the main existing characteristic impedance models.