John Allan Hall
Traditional Active Noise Reduction (ANR) technologies have been limited to active control of frequencies below 750 Hz. These strategies are ideal for tracked vehicle, rotary wing and/or fixed wing turbo-prop noise environments. But these legacy technologies may short of sufficient A-weighted reduction in many high level broad spectral noise situations typical in fast attack jets. Recent USAF sponsored R&D, however has made broadband ANR in the ear canal a reality. Broadband ANR offers significant benefit in targeting overall dBA reduction for environments with significant acoustic energy above 1000 Hz.