Electret microphone MKE-100 (USSR):
Nom. operating frequency range, Hz - 50 .. 20,000. Sensitivity in a free field at 1000 Hz, mV / Pa, not less than - 2.
Average difference in front-rear sensitivity in the range of 250 .. 5000 Hz, dB, not less than 15.
Deviation of individual frequency response from typical, dB, no more - +/- 3.
Frequency irregularity sensitivity in the range of 50 .. 20,000 Hz, dB, no more - 8.
Modulus of total electrical resistance at 1000 Hz, Ohm, no more - 200.
Equivalent sound pressure level due to the microphone's own noise, dB, not more than - 24.
Supply voltage pre. amplifier, V - 2.5 .. 3. The optimal distance of the microphone from the sound source, m - 0.3 .. 0.5.