The Cardioid Plane Microphone is a multi-capsule condenser microphone system with a unique directional characteristicsthat are largely independent of frequency. On the horizontal axis the KEM 970 has the characteristic of a cardioid microphone, whilst on the vertical axis the characteristics resemble a shotgun microphone with a very narrow acceptance angle of about 30°.
The directional pattern is therefore particularly well suited to the most frequently encountered situations where the source to be recorded is widely spread, or moving across the horizontal plane and sound arriving from other directions needs to be attenuated.
Attenuated sound may consist of unwanted noise or reflections from surfaces such as ceilings, tables or the floor. Mounting the microphone physically on its side can significantly reduce feedback problems from sound reinforcement loudspeaker installations on the side walls.
For effective use of the highly directional nature ofthis microphone, a good understanding of thedirections from which wanted and unwanted sounds arrive is important. The more care taken in positioning the KEM 970, the better the results obtained will be. Integrated front facing indicator lights help in positioning the microphone accurately.
Acoustic treatment to improve a room can be an extremely costly exercise, and perhaps not even possible when trying to achieve the average 5 dB increase in operating level that the KEM 970 provides.An added benefit of the KEM 970, as shown in Fig.3,is its ability through skilled use of the sensitivity characteristics, to compensate for level changes if the sound source moves closer to the microphone.