High-output microsized earplug driver system for extreme acoustic environments

Hearing protection is critical when aircraft flight operations create a high-noise environment (130–150 dB) for aircrew and service members. Untreated aircraft noise causes noise-induced hearing loss (NIHL) and poses risks of similar hearing damage in the future. The authors have developed a new microsized smart material actuator (MSMA), a high-output earplug driver for active noise reduction (ANR) hearing protection, based on highly efficient microstructured acoustic exciters. The MSMA consists of a microscale earplug (MEP) with a proprietary acoustic structure, a protective MEP package, and a compact actuation amplifier easily connected to an external ANR controller. Performance tests show that the system produces over 130 dB into a 1-cc trapped cylindrical volume, 6 mm in diameter by 7 mm long, without significant phase delay or noticeable discontinuities in frequency response.