KEM 970 Cardioid Plane microphone

The KEM970 Cardioid Plane “Line Array” Microphone, developed by the Institute for Radio Technology (IRT) in Munich, was engineered and manufactured by Microtech Gefell.

Consisting of 8 critically spaced capsules, this microphone system achieves a vertical acceptance angle of just 30°, being significantly narrower than shotgun interference-tube technology, whilst avoiding the related phase problems.

The wide cardioid characteristic in the horizontal plane allows the KEM 970 to effectively cover a wide sound stage, e.g a choir, or drama production, whilst being able to record typically at distances up to 3 times that of an omni. The very narrow vertical acceptance angle allows the microphone to deal with ease with unwanted reflected sound from above or below.

Popular applications for this microphone include:

• Choir, or drama productions, where the microphone can overshoot an orchestra pit. Sub-mixes of choirs are reported to to exhibit much higher intelligibility due to lower intermodulation.
• Video- and Teleconferencing, where large numbers of participants over both a wide and deep area can be clearly heard.
• Speakers podia - motivated presenters can move freely from side-to-side without level change, while narrow vertical response deals effectively with unwanted reflections from the room

Polar response viewed from side

Polar response from above

 KEM 970 developed in co-operation with the "Institute for Broadcast Technology (IRT)" in Munich.

• Multi-capsule condenser microphone system “Line Array”
• Recording of widely dispersed or moving sound sources
• Records at approx. 3 x distance for same diffuse field ratio
  compared with omni microphones
• Optical display to assist accurate recording angle
• Very narrow 30 deg. polar pattern in the vertical axis effectively suppresses undesired reflections
• Typical increase of feedback threshold by 6 dB in reinforcement applications
• Frequency range 40 - 18000 Hz
• Line level output, two position level attenuation switch
• HP filter switch
• Analog or digital outputs - AES/EBU - DPP

   Acquiring good sound and listening
   accurately to what is happening -
 arguably the most important things
you ever do in professional audio