The Different Microphone Polar Patterns

Polar patterns of microphones are a representation of a microphone’s sensitivity to the sound relative to the angle or direction from which it receives the sound.

In simpler words, a polar pattern decides how well the microphone will hear the sound from various directions. This is known as the directionality of a microphone, and different microphones have different polar patterns depending on the application.

The challenge for sound engineers is to select the right polar pattern microphone for a given application and use the proper technique to capture the desired sound and reject any unwanted noise or feedback. Omnidirectional, unidirectional and bidirectional are the three top types.

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Omnidirectional

Omnidirectional microphones, as the name suggests, are equally sensitive to sounds arriving from all angles or directions. Due to this, there’s no need to aim for omnidirectional microphones in a particular direction.

This is useful when you’re using a lapel microphone to capture the speaker’s voice so that the individual can easily move their head without affecting the sound.

 

omnidirectional

Omnidirectional microphones have their advantages in some situations, but they are less than ideal in several other situations.

They can’t be aimed away from any undesired sources, which can lead to unavoidable background noise and feedback. Furthermore, omnidirectional microphones lack directionality and can’t be used to monitor on-stage feedback, rejecting room ambiance or background noise.

However, the speaker or the source can be moved around without it affecting the sound.

Omnidirectional microphones have the benefit of sounding natural and open as compared to the unidirectional and bidirectional alternatives.

This attribute makes omnidirectional microphones a good choice to be used in studio environments where the acoustics are good or in live performances where the stage volume level is low. They are mainly used when capturing a wide source of sound such as a choir or recording in a studio.

Cardioid

Cardioid microphones are a type of unidirectional microphones and are designed to be extremely sensitive to all sounds entering at the front and least sensitive to the sounds at the back.

This unidirectional pickup of sound means that cardioid microphone is ideal for efficient isolation of unwanted ambient noise. It also offers high resistance to feedback, especially when compared to the omnidirectional alternatives.

cardiod polar pattern

Cardioid microphones are the essential microphones for live performance and the most commonly used unidirectional polar pattern microphone.

They also have a wide pick up area on-axis and the rejection is maximum at 180 degrees off-axis. Cardioid microphones reduce the ambient noise by two/thirds compared to their omnidirectional counterparts.

Cardioid microphones are especially useful if the stage monitors are to be placed directly behind the source. The very first single-element cardioid microphone in the world was developed by Ben Bauer in 1937.

In the past, these microphones used to mix the omnidirectional element with the bidirectional pattern pickup element so that the output could be mixed in equal parts electrically and yield a cardioid pattern. These microphones are used commonly in studio recording when the acoustic environment is less than ideal or for live performances.

Subcardioid

Subcardioid, also referred to as wide cardioid, is an obscure polar pattern. The directionality of subcardioid microphones resembles omnidirectional microphones but not entirely.

It gives an open and natural sound, which is suitable for performances with low stage volume when the sound desired is more organic.

The subcardioid polar pattern is much more resistant to the proximity effect, especially when combined with dual diaphragm elements. However, a drawback associated with subcardioid polar patterns is that they are much more susceptible to feedback.

subcardiod

Their best application is small acoustic and low-volume gigs. The minimal reduction in the sensitivity from the back given by a subcardioid microphone is enough to control feedback but only at a low-volume gig.

Using a subcardioid microphone at a low-volume gig gives you the benefit of natural tone and almost zero proximity effect that comes with a less directional microphone.

Subcardioid polar patterns are often combined with other patterns such as hypercardioid to develop a versatile microphone.

Hypercardioid is ideal for loud stage environments, while the subcardioid is perfect for quiet conditions. It takes on the form of a studio quality microphone as well due to its lower stage volume and reduced feedback risk.

Bidirectional

This is the third main type of polar patterns after omnidirectional and unidirectional. A bidirectional mic features the figure-of-eight polar pattern (ribbon-shaped pattern) which, as the name suggests, picks up sound from the front and rear only.

This unique polar pattern rejects all sounds from the sides i.e. at 90 degrees and only receives sound from the front and back of the microphone.

These bidirectional microphones that feature a figure-of-eight polar pattern are usually ribbon microphones or large diaphragm condenser microphones.

biodirecttional

Their unique design leads to bidirectional microphones having two distinct angles of maximum sensitivity as well as two distinct angles of minimum sensitivity.

As far as their sound is concerned, it resembles the sound of omnidirectional microphones a lot and they deliver a natural and open sound.

The pickup angle or coverage is only 90 degrees on both the front and the rear. In terms of ambient noise pickup, they have the same amount of pickup as cardioids.

Their application is also highly focused and unique, and they are typically used in cases where it’s required to pick up two opposing sources of sound such as in a vocal duet.

Conclusion

Understanding the different microphone polar patterns is all about understanding that the comparison between the polar patterns is only in terms of their application and properties. One polar pattern is not better than the other, generally speaking. However, for particular applications, different polar patterns are more ideally suited.

All the polar patterns briefly discussed find their applications somewhere, but even despite their properties, these patterns require consistent performance across multiple frequencies. This means that a great microphone, regardless of its polar pattern, will perform consistently across the complete frequency spectrum. That’s why polar patterns are used to specific applications but not the quality or performance of the microphone.

Interested to know which microphones are the best regardless of its pattern? Check out our Recording Microphone list.

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