Active Noise Reduction Technology

The proposed effort will actively reduce noise from flight operations at watchstander stations below the flight deck to levels that do not require hearing protection. Long-term hearing loss of personnel is projected to cost the Navy on the order of $12.6 billion over a 30 year retirement period. Active noise reduction (ANR) has long been known as the best method of controlling low-frequency noise but has been limited by available technologies. Recent developments in modern control methods and microprocessors have made active noise reduction a practical, realizable solution for controlling low-frequency noise. Etrema Products, Inc. proposes to implement an ANR system to reduce noise levels from shipboard flight operations by >20 dBA over the frequency range from 50-800 Hz. The proposed approach uses a combination of active structural acoustic control and active noise cancellation by vibrating ship bulkheads and/or speaker panels to actively control noise in ship compartments using the magnetostrictive material, TERFENOL-D. The Phase I effort will be to generate a design concept, demonstrate its feasibility through modeling, and develop a concept validation plan. If successful, the proposed work will reduce costs to the Navy of long-term hearing loss and other detrimental effects of excessive noise exposure.