A coupler-based calibration method for ear-probe microphones

Kren Rahbek Nørgaard*, Efren Fernandez Grande, Søren Laugesen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The calibration of ear-probe microphones can increase the precision of calibrating stimulus levels in situ and of measuring acoustic responses from the ear. This paper proposes a methodology to measure the sensitivity of an ear-probe microphone, requiring only an acoustic coupler and a calibrated reference microphone. The input impedance of the coupler is measured, enabled by a preliminary acoustic Thevenin calibration of the ear probe, and the plane-wave transfer impedance of the coupler is calculated analytically. Using these two quantities, the pressure transfer function between the reference microphone and the ear-probe microphone is estimated. This enables estimating the sensitivity of the ear-probe microphone. The proposed and an existing method were compared, resulting in substantially similar ear-probe microphone sensitivities. The proposed method is practically feasible in producing reliable measurements of sound pressure in the ear canal and calibrating stimulus levels in a clinical setting.
Original languageEnglish
JournalJournal of the Acoustical Society of America
Volume144
Issue number4
Pages (from-to)2294–2299
ISSN0001-4966
DOIs
Publication statusPublished - 2018

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