recordinghacks

Neumann KM 84

Cardioid Pencil Condenser Microphone

The KM 84 is a small-diaphragm FET condenser with a fixed Cardioid pickup pattern. It was the world’s first phantom-powered microphone, built to run on 48v DC. Its design goal was to be as small as possible; the model name ‘KM’ stands for Kleine Mikrofon (“small microphone”).

The model number indicates the powering mechanism (8 = phantom power) and polar pattern (4 = cardioid).

Although discontinued in 1992, the KM-84 remains a favorite of vintage mic enthusiasts for drum overheads and hi-hat applications.

Neumann’s KM 184 was intended to be a replacement for the KM 84, but the two mics sound sufficiently different that the KM 84 has remained a standard by which modern FET pencil mics are judged. (See the KM 184 page for additional discussion of the physical and sonic differences between these microphones.)

The mic is known for having an exceptionally flat frequency response and its ability to maintain its cardioid pickup pattern across the frequency spectrum.

Neumann

The resulting frequency response at an angle of ±135° is almost parallel to the 0° on-axis curve. Attenuation at 135° is about 14dB between 100Hz and 18kHz. As a result, a sound source impinging on the microphone anywhere within a 3/4 arc around it will have identical sound quality, even though at different levels.

The mic shipped with a “wind and pop screen,” Neumann p/n WNS 21.

The capsule, Neumann model KK 64 and later designated KK 84, utilizes an innovative backplate design developed by Neumann in 1964. Whereas most condenser microphone backplates rely on a pattern of through-holes to provide access to the front diaphragm to soundwaves entering from the rear, the so-called “crossed-slit” design incorporates a series of eight intersecting grooves. The grooves allow the sound from the through-holes to be more evenly distributed across the diaphragm. The result is an improvement in polar pattern control and in off-axis frequency response. This “crossed-slit” design is retained in the current Series 180 microphones (including the KM 184).

(Capsule photo credit: Klaus Heyne / GermanMasterworks.com)

The Neumann KM 84 is also known as: KM84, KM84i.

The mic was released in 1966.

Specifications

Pickup Patterns	Pads & Filters
Cardioid (10 mV/Pa; 40 - 20,000 Hz)	Pad: -10dB (Via Switch)

Capsule Dimensions	Impedance	SPL/Noise
Capsule diameter: 20mm	150 Ohms (Low)	Max SPL: 130 dB Self-noise: 17.0 dB(A)

Weight	Length	Max Diameter	Interface(s)
80g (2.82oz)	100mm (3.94'')	21mm (0.83'')	3-pin XLR male (1)

Power Specifications
Requires phantom power Phantom voltage: 48 ± 4v

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