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Frequency response
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Audio Technology / Recording / Microphones / Polar Patterns...

The microphone’s polar pattern should play a crucial role in choosing a microphone for a specific recording application. The polar pattern is a plot of the sensitivity of a microphone as a function of the angle around that device. There are several common polar pattern types used in microphones today. The omnidirectional microphone records sound equally from all directions. Such microphones are most commonly used as built-in or lavalier types. They seem to be very good for recording interviews, though their 360-degree pick-up range introduces too much noise to the signal for it to be used reliably in acoustic analysis.

Cardioid polar patter of a Shure Beta 87a microphone

The cardioid (heart-shaped) pattern is most sensitive to sounds coming from the front. It is 6 dB less sensitive to sounds from 90 degrees to the sides, and, in theory, is completely insensitive to sounds coming from the rear. The most important attribute of a cardioid (directional) microphone is its ability to discriminate between direct sounds (coming from the direction in which it is pointed) and reverberant, unwanted sounds from all other directions. This type of polar pattern usually produces signals that are substantially less noisy than those captured with an omnidirectional microphone CHART>>

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