MIL-PRF-26542 Intended use: This is a noise-canceling dynamic microphone designed for use on a headband type headset at low altitudes or for use in a pressure type oxygen helmet, and at altitudes where the use of an oxygen helmet is required. The microphone is intended to provide communication under the noise conditions encountered in military and civilian aviation aircraft.
Impedance: 4.0 ohms to 6.0 ohms. Resistive load: 5 ohms. Frequency Response: 200 – 6000 Hz Sensitivity at ground level: 34.0dB – 40.98dB (re 1µV) or 50.4µV – 112.0 µV with a Sound Pressure Level (SPL) input of 2.8 Pascal’s (28 dynes/cm2 ) at 1 kHz Sensitivity at 25000ft: Within ± 3 dB of initial ground level sensitivity Noise Canceling: 18 dB Noise Canceling