The Micro-Actuator Speaker System (MASS) for Active Noise Reduction

Research Support Instruments, Inc. (RSI), constructed the first-ever microscale ribbon speaker/microphone, a promising new driver and microphone for active noise reduction (ANR) earplugs, during its Phase I program. RSI proposes to continue the Micro-Actuator Speaker System (MASS) program to develop the technology for use as an active component to a noise reduction system. Micromachined pressure transducers using piezoresistive or capacitive sensing techniques are well developed; this project will instead develop a magnetic speaker/microphone. Magnet-based microphones in macroscale technologies have advantages in sensitivity, bandwidth, ruggednes, and water resistance; similar advantages can be expected on the microscale. Ribbon designs in particular should show strong moisture and flight deck EMI resistance due to the low impedances involved. The Phase II program will involve fabrication of a prototype co-located microphone/microspeaker array, including a circuit board and ruggedized housing; characterization of the new design and demonstration in ANR; refinement of the design, and fabrication of ten final prototype units for delivery to the Air Force. The Phase I program demonstrated that the MASS co-located micro-ribbon speaker/microphone is a valid technology that can address a critical need in ANR, and the Phase II program will be critical to bring the technology to application.