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From the concha to the eardrum

The ear canal is located between the outer ear and the eardrum. This canal provides frequency-dependent amplification of sound. When hearing protection or music earbuds are worn, this transmission changes and the quarter-wave resonance is often lost. With a good acoustic design, this transmission can be specifically influenced.

Acoustics of the Outer Ear and the Effect of Hearing Protection and Earplugs

This publication discusses the acoustics of the outer ear and the impact of in-ear products. The ear canal functions as an acoustic tube with a quarter-wave resonance around 3 kHz. Inserting hearing protection or earbuds alters this transfer. Using ear simulators (such as the GRAS RA0402, compliant with IEC 60318-4) and lumped-element models, the transfer function between the ear and the eardrum is analyzed. This is applied in the design of flat insertion loss for musical hearing protection and the acoustic tuning of in-ear speakers.

Citation for the publication

  • Author: Dr. J.A. de Jong, M.Sc. (Redu-Sone B.V. / ASCEE)

  • Event: NAG Masterclass – Ear Acoustics and the Acoustics of the Ear (Dutch Acoustical Society)

  • Date: January 22, 2025

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