Abstract
Reliable attenuation of hearing protection devices (HPDs) depends not only on their nominal rating but also on correct fit and individual variability. To address the need for simple, on-site verification of real-world earplug attenuation, we developed a mobile application that measures the user’s hearing threshold at 500 Hz with and without earplugs inserted. The system employs an adaptive staircase procedure in which a 500 Hz pure tone is presented through the user’s smartphone. Users adjust playback level themselves until the tone is barely audible. Level adjustments are implemented in 5-dB steps until the first reversal, after which the step size is reduced to 1 dB to refine the threshold estimate. The difference between the two measured thresholds provides an approximation of the achieved attenuation. The app has been deployed internally within an industrial setting and has received highly positive user feedback. Participants report that the procedure is intuitive, rapid, and provides meaningful insights into the actual protection performance they achieve in daily use. Informal user reports indicate that several individuals were surprised by the low attenuation they obtained, while others discovered that switching to a different earplug size significantly improved their attenuation. Because only fully anonymized data are collected, systematic before/after analyses are currently limited. However, early qualitative indications suggest that the tool may help promote better HPD selection and fit, ultimately supporting more effective hearing conservation practices.