Attenuation of hearing protectors: A systematic comparison of subjective and objective measurement methods

Abstract

A key component when selecting a hearing protector is the noise attenuation offered by the device. The subjective Real-Ear Attenuation at Threshold (REAT) test method is the most commonly used procedure to measure attenuation. On the other hand, with the increase popularity of individual fit testing and miniaturization of electronic components, the Microphone-In-Real-Ear approach (MIRE), and its field counterpart F-MIRE, are becoming more appealing and well suited for estimating attenuation in laboratory or in “real world” occupational conditions. In this approach, two miniature microphones are used to measure sound pressure levels in the ear canal under the protector and outside of the protector. This study presents a systematic evaluation of the various factors relating the subjective and objective attenuation values. Experiments on human subjects were carried out where the subjects were instrumented on both ears with microphones outside and underneath their protector. They were then asked to go through...