Active Noise Reduction Earplug and Improved Speech Intelligibility for Aircrew and Deck Crew Personnel with Helmet Integrated Communication Systems

"SYTRONICS proposes Noise Reduction and Improved Speech (NORIS) research to accomplish Phase I objectives, establish a foundation for further research and prototyping in Phase II, and product testing and development in Phase III. Phase I objectives are:propose new design approaches using existing technology for hearing protection of personnel using communication systems; identify performance differences between custom-fit and foam earplugs; compare new materials available; include data on new speechintelligibility technologies; and develop a conceptual design. The proposed work includes: Assessing currently used passive systems, performing comparative analyses and identifying differences in performance with foam earplugs; Performing preliminarystudies to determine passive attenuation requirements by (1) replicating a 1981 Shanks and Lilly study to determine the most sensitive measure of ear canal residual volume; and (2) identifying and verifying the most effective method for estimating residualear canal volume when using deep-seated earplugs; Determining active noise reduction (ANR) requirements using deep-seated ear plugs and a noise sensing microphone; Investigating ANR, Communications Earplug (CEP) and other techniques that hold promise forreducing noise at the inner ear and improving speech communications; Providing a concept demonstration of a preliminary noise reduction system for deck crew with communications. We anticipat