When looking up mic specs, you’ve probably seen terms like “cardioid”, “supercardioid”, “omni”, and “figure-8”. These all refer to the microphone’s polar pattern, which is the way a microphone responds to sounds from different directions.
What Is a Microphone Polar Pattern?
A microphone’s polar pattern is the way it responds to sounds coming from different directions. A polar pattern is mostly determined by the casing surrounding the microphone, and not by its internal design. The term “polar pattern is also sometimes called “pickup pattern” or “directional response”.
What Are the Types of Microphone Polar Patterns?
There are four main types of mic polar patterns: cardioid, supercardioid, omnidirectional (omni), and bidirectional. Each one has unique characteristics that make them ideal for different situations.
Cardioid Patterns
Cardioid microphones are unidirectional, meaning they work best when the signal is directly in front of the mic. They work less well when the signal is off to the side or the back.
The pickup pattern is more or less heart-shaped, hence the name cardioid.
Cardioid mics are great for many applications. You can use them to isolate a signal while rejecting audio from behind.
That said, these mics are best if the audio source is stationary. If the performer is constantly moving off-axis, you may want to try another solution.
Applications for Cardioid Mics:
- Close-miking a single audio signal (vocalist, instrument, etc)
- Isolating an audio signal from a noisy environment
- Avoiding and rejecting audio from behind
Supercardioid & Hypercardioid Patterns
These are similar to cardioid polar patterns, but with a few notable differences.
First, the overall supercardioid shape is comparable to cardioid, but slightly more narrow.
Supercardioid patterns also have a rear lobe or tail. This makes them more sensitive to sounds behind the microphone.
You get a supercardioid pattern by changing the size and number of openings on the microphone casing.
By making these changes, you increase the directionality of the mic while decreasing its sensitivity to the sides.
Hypercardioid patterns are similar to supercardioids, but more more exaggerated.
The pattern is more narrow to the front, making them even more directional. The back lobe is also wider, making hypercardioid mics even more sensitive to sounds from the rear.
Both supercardioid and hypercardioid mics are great for most of the same applications as cardioid microphones. Since the pattern is more narrow, they’re awesome at isolating directional signals.
They’re also better at combating proximity effect, which exaggerates and distorts bass frequencies if the sound source is too close.
That said, super- and hypercardioid mics struggle more in a room with lots of ambient noise.
You also have to be more careful about how you position them. The rear lobe makes them more vulnerable to microphone bleed from other sources.
Applications for Supercardioid & Hypercardioid Mics:
- Close-miking a single audio signal (vocalist, instrument, etc)
- Isolating an audio signal from a noisy environment
- Rejecting sound from the sides
- Reducing proximity effect
Omnidirectional Patterns
An omnidirectional microphone pattern picks up sound equally in every direction.
(Remember: Omni = All)
It doesn’t matter what direction you face an omni mic. It’ll pick up sound the same way regardless.
Omni mics are great for recording multiple sources at once, or for capturing ambient room noise.
On top of all that, omni pattern microphones resist issues like plosives, wind noise, or proximity effect.
That said, you can’t really use them to isolate or reject any signals. Plus, they’re more prone to feedback.
Applications for Omnidirectional Mics:
- Capturing sound from multiple performers
- Recording ambient room noise
- Reducing issues like plosives, wind noise, or proximity effect.
Bidirectional (Figure-8) Patterns
Bidirectional or figure-8 polar patterns pick up signals almost equally on the front and back sides. However, they capture almost nothing on the sides.
The shape more or less resembles a figure-8, hence the name.
Since a figure-8 mic’s sensitivity is so low on the sides, they’re often used to reject sound sources.
Bidirectional microphones are also handy for recording multiple sources at once. For example, you could record two singers with great clarity using only one mic. Otherwise, you’d have to use multiple microphones.
But, you’ll need to be more careful about mic placement when using a figure-8 mic. Since they pick up sound equally on both sides, it’s easy to accidentally pick up unwanted signals from one side or the other.
Applications for Bidirectional Mics:
- Capturing multiple singers or instruments at the same time
- Recording two individuals for a podcast
- Maximizing proximity effect
- Rejecting signals from the sides
Microphone Patterns and Proximity Effect
Most directional microphones change their frequency response as they get closer or farther away from a sound source.
If a mic gets too close to the sound source, it exaggerates lower frequencies. This phenomenon is known as the proximity effect.
Proximity effect is neither a good or bad thing. In some cases, you can use it to add warmth and color to your recordings.
Other times, you don’t want those low frequencies. Supercardioid mics like the Shure Beta 58 can help combat proximity effect.
Further Reading
Understanding more about how microphones work helps you become a better recording and live sound engineer. For that, we have some additional pages that cover microphone basics:
- What is a Flat Response in Music Production? — We cover the basics of frequency response and why you want devices with a flat response when recording or monitoring.
- 5 Simple Ways to Reduce Proximity Effect — We explain what the proximity effect is and some ways you can reduce it.
We also recommend checking out The Recording Engineer’s Handbook by Bobby Owsinski. It covers everything you’ll ever need to know about microphones and recording.
