Development of an advanced hearing protection evaluation system

Acoustic test fixtures (ATFs) are practical and often necessary tools for testing hearing protection devices (HPDs) especially with extremely loud impulsive and/or continuous noise, for which the use of live subjects might not be advisable. Although there have been various standardized and laboratory ATFs from past research, there still exists large uncertainty in the correlation between the attenuation results obtained from ATFs and those obtained from actual human subject tests, particularly for intraaural HPDs. It is suspected that one of the main factors contributing to the discrepancy may be insufficient fidelity in the circumaural/intraaural flesh system, whose underlying dynamics is not yet clear. Therefore the first goal of this research is to better understand this biomechanical system and implement it into a new ATF prototype which emulates circumaural/intraaural HPD attenuation performance. This prototype ATF will be validated against human subjects. This presentation discusses the research methodologies and design strategies for developing this advanced hearing protection evaluation system.