Actuator Design and Development for Optimized CIC Audio

Advancements in subminiature earphone drivers are sought to provide desired improvements in active noise reduction (ANR) earplug attenuation magnitudes and bandwidth. Prior investigations have illustrated a need for improvements in frequency response, sound power output, geometrical configurations, and ease of manufacturing for drivers that are optimized for military ANR earplug applications. This Phase I program begins with theoretical descriptions of existing earphone driver parameters, followed by further investigations of specific conceptual improvements described herein. All Phase I program objectives seek to identify advanced earphone driver designs that are feasible, with low-risk paths to reasonable-cost manufacturing methods. The success of the program will rely on ATI's extensive experience designing completely-in-the-canal ANR earplugs. Past development work has led to precise information about desired open-loop earphone driver frequency response characteristics that will optimize the closed-loop attenuation performance. This information will be used in considering new advancements in electromagnetic and piezoceramic earphone driver concept designs, with an initial prototype available at the end of the Phase I program.