Developing a Methodology for Testing of Hearing Protection Systems

Every day, individuals around the globe are exposed to noises that have devastating long-term effects on their hearing. Noise-Induced Hearing Loss (NIHL) is the second most common form of sensorineural hearing decline behind the age-related loss. NIHL can result from continuous exposure to high-intensity sounds such as heavy machinery or instantaneous exposure to extremely loud sounds, like gunshots and explosions. While passive hearing protection currently exists, the characterization and testing are limited mainly to pressure attenuation levels. There is limited research and information as to the frequency damping characteristics along with the linear and nonlinear performance. Further, the measure of these protections is quantified after creation, with limited criteria on how to design earplugs with desired characteristics. Here, we describe our progress in the development of methods to characterize the linear and nonlinear performance, frequency response, and damping characteristics, as well as investigating the correlation between material properties and performance.