An impedance tube technique for estimating the insertion loss of earplugs

Type de document

Études primaires

Année de publication

2024

Langue

Anglais

Titre de la revue

Journal of the Acoustical Society of America

Première page

898

Dernière page

911

Résumé

This paper proposes a quick and straightforward technique for estimating the insertion loss (IL) of earplugs measured on an acoustical test fixture (ATF) using a commercial impedance tube. In this method, the earplug's acoustic properties (i.e., its transmission loss and the reflection coefficient of its medial surface) are determined from its transfer matrix measured using the three-microphones impedance tube method modified here for the current application. The IL is then estimated using a one-dimensional analytical model of open and occluded earcanals based on the wavefield decomposition theory. The method is evaluated numerically and experimentally from 50 Hz to 6.5 kHz. The numerical study allows for verifying the accuracy of the proposed approach in comparison to a simplified model of an ATF earcanal excited by normal incidence plane wave and diffuse field excitation. The experimental evaluation, which involves six earplugs (including five commercially available ones) representing various earplug families, demonstrates the accuracy of the estimation method, yielding results with a maximum difference of 3 dB compared to ATF measurements, on average, among the tested earplugs. © 2024 Acoustical Society of America.

Mots-clés

Protège-tympan, Earplug, Critère de confort, Comfort criteria, Oreille, Ear, Essai du matériel, Equipment testing, Coefficient d'absorption acoustique, Sound absorption coefficient

Numéro de projet IRSST

n/a

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