Audio Technology

Recording

Introduction
Frequency response
Polar Patterns
Proximity effect
Cabling and phantom power

Recording environment
Microphone placement
Signal processing and special effects

Introduction
Analog recorders
Digital recorders
DAT recorders
Minidisk recorders
PC card and CD-R recorders
Hard disk recorders

Processing

Improving audio digitization
Digitization workflow

Introduction
Preparing files for analysis and delivery
Digital restoration
LPC in acoustic analysis

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>>

Audio Technology
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Last updated: 2002