A Beginner's Introduction to Microphone Polar Patterns (2024)

When it comes to microphone polar patterns, you’ve most likely heard the following 3 terms a million times:

Cardioid,Omnidirectional, andFigure-8.

But what do they actually MEAN?

And why are they SOimportant when choosing the right mic?

If you’ve got questions, and you want answers…

Then here’s what I have for you:

In this post, I’ve assembled this easy-to-read guide entitled…A Beginner’s Introduction to Microphone Polar Patterns.

A Quick Definition of Microphone Polar Patterns

A microphone’spolar patternis the 3-dimensional space surrounding the capsule where it is MOST sensitive to sound.

The 3 basic patterns are:

• omnidirectional
• figure-8
• cardioid

Here’s a diagram showing how they look:

As you can see…

• Mic 1has anomnidirectional pattern–meaning the entire red area is equally sensitive to sound.
• Mic 2has afigure-8 pattern–meaning the two blue areas on the front and back are sensitive, while the sides are ignored.
• Mic 3has acardioid pattern–meaning the green area in front of the mic is most sensitive, the sides are less sensitive, and the rear is ignored.

Common Microphone Polar Pattern Variations

Other than the3 basic patterns, you also see:

• Supercardioid– which is likecardioid, butNARROWER, with a small bulb of rear sensitivity.
• Hypercardioid– which is like supercardioid, butnarrow still, and with a larger bulb in the rear.

Some mics, known as “multi-pattern mics”allow you to switch betweenseveral polar pattern options as needed.

Now here’s where all this technology came from…

How These Polar PatternsCame to Be

In the earliest days of microphone technology,there wereonly 2 polar patterns:

1. Omnidirectional
2. Figure-8

Omnidirectional Mics

Originally known as“pressure” microphones, their diaphragms measured sound pressure at a single point in space.

Because theyhad no directional information, theywere equally sensitive to sound from all directions.

Figure-8 Mics

Commonly known as“pressure gradient” microphones,they measured the DIFFERENCE in pressure between either side of an open diaphragm.

This meant that they were very sensitive to sound from the front and rear, butalmost completely deaf on the sides.

The Birth of Cardioid Mics

Eventually someone discovered that by combiningthe signals of BOTHomnidirectionalANDfigure-8mics…

Here’s what happens:

• In the front– the positive signals combine to be 2x as strong.
• On the sides– the signal from the omni remains the same.
• In the rear– the negative signal of the figure-8 cancel out the positive signal of the omni.

The result becamewhat we know today as a standardcardioid polar pattern.

Here’s a diagram to illustrate it:

Eventually engineers designednewcardioid capsulesthat were essentially hybrids of the original two designs. Soon afterward, came these next patterns:

Supercardioid/Hypercardioid

The next major advancement came whensomeone realized that cardioid patterns could be madeeven MORE directionalby mixing MOREfigure-8 signal with LESS omni.

As a side effect, this would also create a small bulb ofsensitivity emerging from the rear.

This new pattern became known assupercardioid, andthenarrower version known ashypercardioid.

In this example diagram, I show how it works by combining1 part omniwith2 parts figure-8:

Now let’s move on…

How Multi-Pattern Mics Work

Rather than requiringa separate mic for every job…engineers came up with an ingenious ideato cram a TON of versatility into just one mic.

They realized that…simply by varyingthe output fromtwo back-to-back cardioid capsules, you could recreate virtually any polar pattern imaginable.

For example:

• By combining both cardioid signals, you get anomnidirectional pattern.
• By combining both but reversing the polarity of one, you get afigure 8 pattern.
• By turning off one, and using the other, you get acardioid pattern.

And that’s how we eventually got the multi-pattern mics we use today.

The most famous example of this type of mic? A USB mic known as the Blue Yeti –(Amazon). Check it out.

Next up, let’s see how all these patterns are used to actually record stuff…

When to UseCardioids

The advantage of usingcardioid micsseems simple, right? Itrecords where you point it, and ignores everything else. Which is why it is the obvious choice for vocal mics.

But here are some less-obviousexamples when it’s ESPECIALLY useful:

• Miking up a drum kit – With so manyinstruments so close together, isolation might seem impossible. But it CANbe done, with the right cardioid mics, positioned in the right spots.
• Live performances– On-stage, when sounds are coming at you from all directions, cardioid mics are great maintaining isolation and preventing feedback.
• Untreated rooms– In rooms with poor acoustics, close-miking with cardioid mics can workwonders at minimizing reflected sound.

Now theymight seem idealin most cases..but cardioid mics DO have drawbacks…

The two BIGGESTones being:

• Off-axis coloration– With most cardioid mics, you see a drop in high frequency sensitivity as sounds move further off-axis. This could be bad, for instance, with an inexperienced singer unconscious of his head movements.
• Proximity effect– A phenomenon exclusive to cardioid mics…proximity effect is a boost in bass frequencies that results from extreme close-miking. Using the same “inexperienced singer” example, you can see how this might also cause problems.

Supercardioid and hypercardioid patterns, while essential for filmmakers, are not commonly used in the recording studio.

When to UseOmni’s

Because they are SO prone to off-axis spill…Omnidirectional mics aren’t nearly as popular as they were prior to the invention of the cardioid pattern.

But by no means does that make themirrelevant. For example…

Here are commonsituations when they’re preferable:

• When recordingthesound of theroom– such as withroom mics for drums.
• When recording a widesound source– such as an orchestra, choir, or grand piano.
• When recording a moving target–such as an acoustic guitar player who can’t sit still.
• When recording in stereo– such as with the common A/B technique.

Compared to cardioid mics, omnidirectional mics offer the following advantages:

• immunity to proximity effect
• lower self noise
• a frequency rangethat typically extends a full octave lower
• less coloration of off-axis sounds

This lastadvantage is especially true with small diaphragm omni mics. That is why most precise measurement microphones (like Earthworks mics for example) are small diaphragm omni’s.

When to UseFigure-8

So why EXACTLYwould youwant a mic that was equally sensitive on bothsides? It doesn’t seem very useful, does it?

The cliche example you always hear is…to record a duet of singers facing each other.

While it might be great in that situation…how often does that ithappen? Almost never.

It’s much more common to use figure-8 mics for one of the following3 reasons:

1. for stereo recording
2. withribbon mics
3. for maximum isolation of off-axis sounds

Forstereo recording, figure-8 mics are required to perform both theBlumlein Pair, andMid/Sidestereo techniques.

Withribbon mics, the physical make up of the design oftenrequires a figure-8 polar pattern. If you like ribbon mics for their sound, the figure-8 pattern simply comes as part of the package.

Toisolate instruments in close proximity, figure-8 mics are ideal because they completely reject sound from the sides.

With smart positioning, you can achieve moreisolation with a figure-8 mic thanwith any other polar pattern. One common trick is to place acoustic absorption at the rear end of the mic to block out any unwanted noises.

Putting Your New Knowledge Into Practice

So now that you know all the basics of microphone polar patterns, it’s time to put this knowledge into practice.

While all these facts may be simple enough in theory…the onlyway to really get a feel for microphone polar patterns is toexperiment.

Take some time to record different instruments, with different polar patterns, in different rooms…and listen to the differences ineach combination.

Eventually you get a feel for what works and what doesn’t.