KEM 975

From Microtech Gefell:

The cardioid plane microphone KEM 975 is a line array microphone system with a largely frequency-independent polar pattern, which – in the horizontal plane – has the features of a cardioid microphone and – in the vertical plane – the features of a directional microphone with an operating angle of approx. 30 degrees. Thus, the polar pattern is adapted to the frequent case that the sound source to be captured is wide in space or moves around in it and, at the same time, sound coming from other directions is to be suppressed. The sound to be rejected may consist of disturbing noises or reflections which come from the ceiling, table surfaces or floor areas. Due to its directional characteristics, the KEM 975 can be used for recording sound sources that are very extensive in width and depth or moving sound sources. Since the complete signal processing is analogue, there are no signal delays.

Below approx. 800 Hz, the KEM 975 cannot maintain its clubbed directivity in the vertical plane anymore due to its length and approaches a cardioid polar pattern more and more with decreasing frequency. With a process developed and patented by the Institut für Rundfunktechnik (Institute for Broadcasting Technology), the directivity and the directionality are increased in this frequency range by using the optional attachable Delta capsule which forms an equilateral triangle together with the two outermost capsules of the KEM 975. Thus, a frequency-constant directivity index is realised across the entire frequency range down to below 100 Hz. The result is a better spatial separation of sound sources with low-frequency signal portions and a more consistent spaciousness in the recorded signal over the frequency spectrum. This is particularly advantageous for music recordings. If the KEM 975 is used for video conferences, or as a speaker’s microphone on a lectern or desk, it can be used without the Delta capsule, as speech frequencies are above the threshold where the Delta capsule is needed.

The KEM 975 was developed in collaboration with the Institut für Rundfunktechnik in Munich.