Microphones are available with several different pickup patterns. That is, they are more sensitive to sounds coming from certain directions. In broadcasting, we work primarily with three patterns: Omnidirectional, Cardioid, and Hypercardioid.
These diagrams show the sensitivity of the microphone, with the mic pointing “up” in each case.
This is popular with TV reporters for general outdoor work. It picks up the sound of the surroundings as well as the reporter’s voice. Aiming is not critical. However, when used indoors, any imperfections in the room’s acoustics will be easily heard.
Picks up very well directly in front of the mic. Lower sensitivity from the sides, with little pickup of sounds coming from behind the mic. On stage, this pattern reduces the chance of feedback from the sound system. In a studio, the cardioid pattern helps to isolate the sound being recorded. It will hear mostly the voice or instrument, with very little of the room’s ambience.
This pattern is found in long “shotgun” mics. It doesn’t reach any farther in the forward direction than a regular cardioid, but by reducing the pickup from the sides, what’s directly in front is more easily heard. There is a small amount of pickup from the rear.
In the field, shotguns mics are used to pick out a particular sound at a distance (hearing a certain voice in a crowd). In the studio, it is often favored by voice-over artists for its articulate pickup as well as rejection of an imperfect room.
It’s not unusual for a reporter to have one of each type of pattern available. In the broadcast studio, the cardioid pattern is the most popular.
By choosing the correct pattern for the job, you will more clearly hear the sounds you want, and not the stuff that you don’t.