Shotgun microphones are particularly useful in recording situations where a microphone cannot be positioned within the desired distance of the sound source to produce a sufficiently loud signal level.
Typical applications are film and video recordings, where the microphone should not appear in the picture.
The KMR 82 is very often used on stage. The KMR 81 has been specifically designed for electronic news gathering.
In principle, Neumann shotgun microphones use a combination of a pressure gradient transducer and an interference tube. If the wavelength of the frequency is longer than the tube length, the microphones work as pressure gradient transducers. At higher frequencies they operate as interference transducers for lateral sound. Off-axis sound sources are picked up with reduced level, but without coloration.
Therefore, the microphones are well suited to record individual instruments of an orchestra. The pickup areas of several shotgun microphones may even overlap as, for example, during recordings on a large stage, without causing any problem.
The KMR 81 and KMR 82 are less sensitive to wind and pop noise when compared to the KM 150 miniature microphone with a similar high directivity. Both shotgun microphones feature extremely low self noise, good impulse response, and high output level.
KMR 81 and KMR 82 are shotgun microphones with a very directional characteristic.
The microphone capsule is positioned inside a housing tube that is acoustically open but has a high flow resistance.
The directional patterns of the microphones are lobe shaped. The attenuation of lateral sound is practically independent of the frequency.
The KMR 82 has a frequency independent directivity within a pickup angle of 45° for audio signals that determine the tonal balance of the program material. For the KMR 81, this angle is 90°.
Filter and attenuation KMR 81 i
KMR 81 i The microphone has a 10 dB attenuation switch to prevent the input of the following unit from overloading.
A second switch activates a 200 Hz high-pass filter. Toward the lower frequencies the sensitivity of the microphone is attenuated by approximately 15 dB at 50 Hz. The frequency range above 200 Hz is unaffected.
Filter KMR 82 i
Between 2 kHz and 15 kHz the KMR 82 has a boost to compensate for HF transmission losses in air when recording distant sound sources.
This may overemphasize any sibilance if the microphone is used close-up.
Therefore, a two-position slide switch allows to select the setting that is best for balanced upper frequencies.
The KMR 82 has a high-pass filter to suppress subsonic interference. The cutoff frequency may be raised to 120 Hz ( - 3 dB) with a built-in two-position slide switch.
Use on location
The shotgun microphones feature very high output capability and a remarkably low self-noise level.
Their low power consumption, light weight, and low sensitivity to wind and handling noise, make them ideal tools for news gathering on location.
Small dimensions, together with a balanced center of gravity, make handling easy without any whiplash effect.
However, when on location and during strong wind conditions, we recommend using an additional wind screen (included as standard accessory). The wind screen is made of polyurethane foam and also serves as soft padding of the microphone in its leather carrying case.
For mobile use a handle and an elastic suspension are available. An active handle with a built-in battery power supply makes an external phantom supply unnecessary.