The Neumann KM 84 is a fixed-cardioid, small-diaphragm FET condenser microphone developed to meet the requirement for a compact condenser microphone compatible with 48 volt phantom powering. Designed around the Neumann KK 64 capsule, later designated Neumann KK 84, the microphone employs a pressure-gradient transducer principle and delivers a highly consistent cardioid polar pattern across the audible frequency spectrum.
The circuit design allows the microphone to operate from standard 48 volt DC phantom power by drawing current symmetrically across the modulation pins, ensuring no voltage potential appears at the audio output.
The compact construction of the Neumann KM 84 was a key design goal, resulting in a body diameter of 21 mm and a length of 110 mm. The microphone incorporates a switchable 10 dB attenuation pad placed at the gate of the field-effect transistor, allowing the microphone to handle high sound pressure levels without overloading the amplifier stage.
With the pad engaged, the microphone can accommodate sound pressure levels up to 130 dB SPL without distortion. The Neumann KM 84 was supplied with the Neumann WNS 21 wind and pop screen and was manufactured in Germany until its discontinuation in 1992.
