Bayesian decay time estimation in a reverberation chamber for absorption measurements

Jamilla Balint*, Florian Muralter, Melanie Nolan, Cheol-Ho Jeong

*Corresponding author for this work

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Abstract

This work investigates the use of the initial decay time to obtain the Sabine absorption coefficient from measurements conducted in a reverberation chamber. Due to non-uniform distribution of sound absorption in the test chamber, measured energy decay functions exhibit multiple slopes, which cannot be evaluated unambiguously using linear regression as prescribed in the current standard (ISO 354, International Organization for Standardization, Geneva, Switzerland, 2003). As an alternative, this study proposes a Bayesian framework that allows estimating multiple decay parameters, hence capturing more accurately the energy decay features. Measurements are carried out in a reverberation chamber with and without diffusing elements to investigate the influence of diffusers on the absorption coefficient and on the decay process. Measured absorption coefficients of a porous sample are compared to theoretical values estimated with a transfer matrix model. The results show that the Sabine absorption coefficient calculated using the shortest decay time agrees well with the size-corrected theoretical absorption coefficient.
Original languageEnglish
JournalJournal of the Acoustical Society of America
Volume146
Issue number3
Pages (from-to)1641-1649
ISSN0001-4966
DOIs
Publication statusPublished - 2019

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