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:
Picks up sound evenly from all directions (omni means "all" or "every").
Picks up sound predominantly from one direction. This includes cardioid and supercardioid microphones (see below).
- Bi-directional or figure-of-eight
Picks up sound from two opposite directions.
***The following graphs are called polar patterns.
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.
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.
This is the cardioid or "heart shaped" pattern that picks up less from the sides at the expense of some sensitivity to the rear.
Picks up sound equally from two opposite directions.
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.