One of the first questions I asked myself when learning about recording my own music at home was ‘what is a polar pattern?’. It almost sounds like something related to the weather. Like a lot of audio terms, the meaning isn’t always so clear and obvious. You have to do a bit of digging and reading to make sense of the jargon. That’s exactly what I had to do when I first started and that’s why I put my website together. To help people like you asking the same questions that I did when I began. In this article I’m going to cover what a polar pattern is, the different types, their applications, and give you some ideas about which type of microphone you should buy.
What is a Polar Pattern?
A polar pattern refers to how a microphone picks up sound. A microphone can pick up sound in front of it, all around it, or behind and in front of it at the same time. Take a look at the image above and you can see that each polar pattern has its own shape and name. But why are there different polar patterns? It’s a great question. The answer is simply that each polar pattern has a unique way to pick up audio. Each polar pattern can serve different purposes, ultimately giving us more flexibility and versatility. Sound is a complex and beautiful thing. Audio engineers, musicians, and producers all want to capture it in the best way possible. So, the more options we have to do so, the better. Let’s examine each type of polar pattern in detail, and their common applications.
Cardioid Polar Pattern
The word cardioid originates from the Greek word meaning heart. And if you look at the first diagram in the article with a top down view, you can see that a cardioid polar pattern is heart shaped. This shape acts as a perfect sweet spot. It’s most sensitive at the front of the microphone whilst capturing enough audio at the sides to give it a natural sound. Simultaneously it rejects audio behind the microphone, eliminating background noise.
For these reasons a cardioid polar pattern is the go-to for most applications. It’s an incredibly versatile polar pattern which is used for pretty much everything from live sound, broadcasting, and in recording studios. If you need to close mic a sound source, reject audio from behind and maintain a natural sound, then a cardioid polar pattern is your best choice.
Hypercardioid and Supercardioid Polar Patterns
Both hypercardioid and supercardioid are closely related. As the terms ‘hyper’ and ‘super’ suggest, they have a more direct and focussed polar pattern than cardioid. They reject much more audio from the sides but as a consequence are a little more sensitive to audio behind them. They are superb for isolating sound sources and are less prone to feedback due to their side rejection, making them a great choice for live sound environments.
Cardioid Polar Pattern Drawbacks
Nothing is perfect in life and cardioid microphones are no exception. There are some reasons why they can be a little troublesome. Firstly, most cardioid microphones can drop in sensitivity within the high frequencies as a sound sources moves further away off-axis. This is known as off-axis coloration, and could be a problem if you have a singer who likes to move around lot, for example.
The second issue is called the proximity effect. When any sound source is too close to a cardioid microphone, there is a significant boost in the bass frequencies. The resulting sound can be boomy and muddy. It’s something to be aware of when using cardioid mics, but as long as you don’t close mic a sound source to the extreme then you won’t have any problems.
Omnidirectional Polar Pattern
An omni polar pattern is a perfect sphere, resulting in the microphone being able to pick sound all around it equally. This may seem strange at first, as often we don’t want to capture unwanted disturbances and focus only on our sound source. So, why would we want to record audio all around us? An omni polar pattern is superb for picking up a room’s ambience. Can you think of any rooms or situations when an audio engineer would want to do this?
There are many spaces such as a cathedral or church where you can find a long and lush reverb. There have been many situations when either a small quartet, or even a large orchestra recorded in such environments. An audio engineer would use cardioid microphones to close mic the instruments, and then place omni microphones spread throughout the building to capture the room ambience, caused by reverberation. The resulting sound is a beautiful and powerful one. If you need to capture a wide sound source or the rooms’ ambience then an omni polar pattern should be your go-to.
Figure-of-Eight Polar Pattern
The design of a figure-of-eight polar pattern allows the microphone to pick up sound directly in front of it and behind it, whilst simultaneously rejecting audio at the sides. Seems weird right, why would you want to do that? A typical example is to record a duet of singers singing opposite each other, or perhaps if you only have one microphone and need to record two people during an interviewer sitting opposite each other. Figure-of-eight polar pattern microphones are also used for the Blumlein pair, and mid/side stereo recording techniques. Additionally, as they reject audio so efficiently well from the sides, they are great for isolating sounds in close proximity.
Shotgun Polar Pattern
Shotgun!? What a name for a type of microphone and polar pattern. Don’t worry, they’re not dangerous. If you refer back to the first diagram in this article, you can see that the shotgun polar pattern is exceptionally narrow and focussed. This makes it flawless at recording a sound source directly, whilst eliminating background noise, and rejecting sound at the sides; which is why they’re always used on film sets for actors’ dialogue.
Shotgun mics are attached to boom poles and it’s the boom operators’ job to point the boom mic at the actor who’s speaking at any given moment. They have to be fast! Imagine if they didn’t move quickly enough and missed a line of dialogue. I doubt the director would be very happy… As well as being ideal for dialogue, shotgun mics are great for capturing live speeches, talks, and sound designers frequently use them to record isolated sounds in detail.
Which microphone should you buy?
Know you know about polar patterns, the next thing you may be asking is which type should I buy? To answer that, you first need to know about the most common types of microphones.
Dynamic Microphones
Dynamic microphones are usually robustly built and less sensitive than condenser microphones. They tolerate loud sound sources exceptionally well such as drums and guitar amplifiers, which is why they are frequently used for live sound environments. Dynamic microphones also eliminate background noise well, making them ideal for podcasting, live streaming, speeches, or singing when you don’t want to record the room ambience.
Dynamic mics usually have cardioid, hypercardioid, and supercardioid polar patterns, and are connected via XLR cables. So, you will need to buy an audio interface to use them, you can read all about that in my article ‘What is an Audio Interface?’.
Condenser Microphones
Condenser microphones are much more sensitive than dynamic mics, which makes them great at recording more detail, nuances, and higher frequencies. As they are more sensitive, they record more of the rooms’ ambience, can’t tolerate loud sound sources well, and are more prone to feedback; which is why you wouldn’t normally use condenser microphones for live environments.
Condenser microphones are used constantly in recording studios for singers, drum overheads, stringed and acoustic instruments. Whenever you want to record a sound in detail, a condenser microphone is your go-to mic. They are also connected by XLR cables, plus they require phantom power (48v), so you will also need to buy an audio interface. Condenser microphones come in two sizes, small and large diaphragm condenser microphones. Condenser mics use cardioid, omni, and figure-of-eight polar patterns, and some, like in the image to the left have the option to switch between several.
Now You Know All About Microphones
Now you know the answer to ‘what is a polar pattern?’. You know the different types, their names, their applications, and the kind of microphones available. Want my advice? Just buy a microphone and start experimenting. That’s always the best way to learn. Have fun with it. If you don’t have a very high budget, just buy a cardioid microphone and go from there. If you have a higher budget, consider a microphone with a choice of polar patterns. Regardless of whatever microphone you purchase, enjoy the learning process. There are NO RULES in recording music or audio. Some of the greatest recording techniques and sounds for movies or songs were created by accident, in an unorthodox way. That’s the beauty of it.
Did you enjoy you find this article helpful? Or do you have any other questions? Please feel free to reach out to me in the comments.
Chris