Monitoring sound pressure at the eardrum for hearing conservation

A study was conducted to describe a probe microphone assembly to monitor sound pressures at the eardrum for hearing conservation. The probe microphone assembly permitted the uncertainty in probe-tip position to be eliminated and the transfer function to the eardrum to be estimated. The device was attached to an ear mold designed to self-locate within the concha and ear canal and position the probe tip reproducibly. The device consisted of a miniature probe microphone and a customized ear-mold. The ear mold was fabricated from an ear impression that was obtained for each subject following established audiological procedures. The ear impression provided the contour of the perimeter of the concha and cymba, which was required to produce the 'C'-structure used to position the ear mold external to the ear canal.