Each microphone has a property or characteristic called directionality (directional properties). This property describes the microphone’s sensitivity to sound from different directions. There are microphones that are able to capture sound from all directions with the same quality, there are those that are only able to pick up sound from one direction or a certain combination of directions.
Certain microphones are usually accompanied by a graphic representation in the manual or promotional material to illustrate the directionality property of the microphone for easy understanding. This graphic representation is commonly called a polar pattern. Here are some common examples of polar patterns that illustrate the directionality of a microphone.
Directional properties on microphones are grouped into three main categories:
Ability to capture the sound of the same quality from all directions. The sound reproduces by the omnidirectional microphone such as SEM-01 and SEM-02 are natural. They capture not only the direct sound but also the airy sound around it. Although it captures surrounding sound, the application of SEM microphone is close miking, so the unwanted sound can be minimized in volume and more signal is accepted.
The ability to pick up sound is more dominant from one direction. This category includes both cardioid and hyper-cardioid microphones.
Cardioid which means “heart-shaped” is one of the patterns of capturing sound on a microphone. The sound is captured mostly from the front and a little area on the side and rejecting sound mostly from behind the capsule.
It prioritizes sound from the direction where the mic is directed but there is still room for mic movement and ambient noise.
The cardioid-type mic is very flexible and ideal for general use. Most handheld mics are cardioid. There are many variations of the cardioid pattern (including the hyper-cardioid described below)
This is an exaggerated version of the cardioid pattern. Highly directional and eliminates most side and rear sound. Because of the hyper-cardioid design that is thin and long, this type of microphone is often called a shotgun microphone.
It is usually used to isolate sound from only one subject or one direction when there is a lot of ambient noise, to capture sound from distant subjects.
By eliminating ambient noise, the sound from one direction of the cage becomes less natural. Inserting audio recordings from other mics will help (e.g. constant background noise at low volume)
Care needs to be taken to maintain the consistency of the sound. You will lose audio if the mic is not always aimed at the subject.
The shotgun shape can increase the sensitivity to the rear area. Hence, the sound reproduced is less natural and has a certain coloration to the audio captured.
Capable of capturing sound from two opposite directions.
Uses a figure-eight pattern and is able to pick up sound evenly from two opposite directions.
Uses: Situations that require the form of a polar pattern like this are rarely found. One possibility is when you are interviewing two people facing each other where the mic is between them.
This type of mic can also be used for M/S miking technique combined with an omnidirectional mic/ cardioid mic. More about M/S (MId-Side) technique later on various miking techniques.
So that are the polar patterns in the microphone.
Hopefully, you get the idea now.
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