Development of a 50 dB ANC Ultra-Plug

An active noise control (ANC) earplug with communications capability is proposed. The earplug implements a new passive attenuation feature that will improve attenuation by 10 dB(A) over traditional earplugs. When used in combination with the ANC and apassive earmuff, over 50 dB(A) of noise attenuation will be achieved. The attenuation of the system will be limited only by bone-conducted noise. The bone-conducted noise is minimized in the ANC earplug compared to traditional earplugs. Speechcommunications will be sensed using a novel and superior approach. RTH Corporation will deliver to the Air Force an ANC earplug prototype that has been tested on an acoustic test fixture as well as on one human. The use of the ANC earplug with an earmuffwill provide noise attenuationsuperior to any personal hearing protection device. This technology is directlyapplicable to the civilian aircraft environment as well as manufacturing plants,construction sites ... The improved attenuation results in superior protectionfrom hearing trauma and improved speech intelligibility.