Micro-Sized Smart Material Earphone Driver

The U.S. Air Force needs an advanced high output subminiature earphone driver for active noise reduction (ANR) to protect aircrew from hearing damage in noisy environments. To address this Air Force requirement, Physical Optics Corporation (POC) proposes to advance our development of the new micro-sized smart material actuator (MSMA), a high-output earplug driver for ANR hearing protection, based on highly efficient microstructured acoustic exciters. The MSMA system consists of a micro-scale earplug (MEP) with POC’s unique acoustic structure, a protective MEP package, and a compact actuation amplifier easily connected to an external ANR controller. In Phase I POC has demonstrated the feasibility of the MSMA concept by developing a linear actuation amplifier and ultraefficient MEP structures without moving components, fabricating a Phase I MSMA system, and demonstrating that the system produces high output sound, up to 130 dB, within a 6 mm diameter by 7 mm long cylinder. In Phase II we will design and build fully functional MSMA engineering prototypes that produce overall high-fidelity sound at more than 130 dB from 800 to 5000 Hz with no phase delay within a 1 cc trapped volume. POC will test the MSMA system in a realistic environment to verify its performance.