Laboratory measurements for objective evaluation of earplug fidelity

Abstract

Musicians and concertgoers can easily be exposed to dangerously high noise doses that lead to hearing loss, and earplug use is often encouraged during loud musical performances. Traditional earplugs for industrial use can distort musical signals reaching the ear to the extent that users find their use disorienting and uncomfortable. High fidelity earplugs are designed to preserve musical sounds better than traditional earplugs by presenting a flat spectral attenuation of sound reaching the ears. At present, it’s not clear how to quantitatively compare different models in an analogous way to other devices in the high-fidelity sphere such as loudspeakers and amplifiers. In this presentation, a suite of laboratory measurements and derived metrics are proposed that lead to a comprehensive evaluation of earplug fidelity in terms of insertion loss levels, flatness, polar distortion maps, and temporal skewing. Initial results for a range of devices are presented, followed by a discussion of future directions.