Microphones 101 B: Pickup Patterns

Directional Properties

Every microphone has a property known as directionality. This describes the microphone's sensitivity to sound from various directions. Some microphones pick up sound equally from all directions; others pick up sound only from one direction or a particular combination of directions. The types of directionality are divided into three main categories:

  1. Omnidirectional
    Picks up sound evenly from all directions (omni means "all" or "every").
  2. Unidirectional
    Picks up sound predominantly from one direction. This includes cardioid and supercardioid microphones (see below).
  3. Bi-directional or figure-of-eight
    Picks up sound from two opposite directions.

***The following graphs are called polar patterns.

Omnidirectional

Uses: Capturing ambient sound; Situations where sound is coming from many directions; Situations where the mic position must remain fixed while the sound source is moving.
Notes:

  • Although omnidirectional mics are very useful in the right situation, picking up sound from every direction is not always desired. Omni sound is very general and unfocused - if you are trying to capture sound from a particular subject or area it is likely to be cluttered by other sources.
  • Omnidirectional microphones have no proximity effect*.

Right-click here to download pictures. To help protect your privacy, Outlook prevented automatic download of this picture from the Internet. Omnidirectioal

Cardioid

Cardioid means "heart-shaped", which is the type of pick-up pattern these mics have. Sound is picked up mostly from the front, to a lesser extent the sides, and minimally from the rear.
Uses: Emphasizing sound from the direction the mic is pointed while leaving some latitude for mic movement and ambient noise. Controlling feedback.
Notes:

  • The cardioid is a very versatile microphone, ideal for general use. Handheld mics are usually cardioids.
  • Cardioid mics have proximity effect.

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Supercardioid

This is the cardioid or "heart shaped" pattern that picks up less from the sides at the expense of some sensitivity to the rear.
Uses: When more directionality than the cardioid is desired. Can be more effective against feedback.
Notes:

  • Supercardioids have more proximity effect than cardioids.

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Figure-of-Eight

Picks up sound equally from two opposite directions.
Uses: Figure-of-eight microphones have uses in various stereo and ambient techniques. They also work well when capturing two people facing each other (like across a table). The very-low side sensitivity can be helpful controlling feedback and leakage. The pronounced proximity effect is often used when more “fattening” is desired (guitar amps and vocals).

Notes:
Figure-of-eights have more proximity effect than supercardioids.

Right-click here to download pictures. To help protect your privacy, Outlook prevented automatic download of this picture from the Internet. Bidirectional

Variable Pattern
Some mics allows you to adjust the polar pattern continuously from omnidirectional to figure-of-eight by turning a knob on the front of the microphone.


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