Advanced Subminiature Loudspeaker/Earphone Driver

The noise levels on an aircraft carrier flight deck can approach 150 dB, an environment in which personnel must work, communicate, and avoid danger. The attenuation required cannot be achieved by passive or active means alone, so they must be combined. Achieving high levels of attenuation by passive means requires the use of a deep insert earplug and possibly an external muff as well. The driver for the active system therefore has to fit within the envelope of the earplug, and be able to produce sound pressure levels at the eardrum high enough to effectively cancel the noise at that location. Using a systems model for the ANR earplug, we have determined in Phase I that three different basic designs (one electromagnetic and two electrostatic) have the potential for meeting these and other requirements. The purpose of the work proposed here is to design and fabricate specific prototype units for full evaluation, and then select the most promising candidate for final delivery and incorporation into the ANR earplug.