| Polar Patterns
We’ll start with a good definition:
A microphone's directionality or polar pattern indicates how sensitive it is to sounds arriving at different angles about its central axis. ~ wikipedia.org In english that definition means:
Microphones can be pointed towards or away from sounds. If its pointed away from the sound, the mic will not "hear" the sound as well or clearly.
What does this mean exactly? And how does it help you? Well, hopefully after reading this, you’ll be masters of your polar pattern domain!
Polar patterns can be split into four basic categories:
It is most common for a microphone to have a single polar pattern, or to have the option to switch between 2 or 3.
Cardioid
 Cardioid mics, often referred to as unidirectional mics, are probably the most commonly used type of microphone in both studio and sound reinforcement situations. The shape of a cardioid pattern is similar to the shape of a heart, with the rear of the mic having an inward dip.
These mics are very good at picking up sound coming from the front of the capsule while rejecting sounds from the rear. It is not as simple as it sounds though. High frequency response will roll off much quicker as you go around the side of the capsule, in other words they won't be as loud from the sides.
Low frequencies are the opposite; a cardioid mic exhibits slight omnidirectional characteristics at lower frequencies, resulting in the response NOT rolling off as much as you go around the sides of the mic.
Probably the most common cardioid microphone is the SM57.
A cardioid pattern is included on most multi-pattern microphones.
What they are good for:
- Cardioid mics are used for everything, even picking up room ambience.
- They are the most popular choice for many instruments because they give you the rejection of room sound, other instruments, and extraneous noise.
Proximity Effect:
Cardioid microphones also exhibit an effect called “proximity effect” or “bass tip-up.” This is a boost in low frequency response at close proximities. For example a singer that is 1 inch away from the mic will have a much bassier tone than one 6 inches away. Keep this in mind and use it to your advantage.
Hyper-Cardioid
 Also known as super cardioid, hyper cardioid mics have a pick-up pattern that resembles a cardioid pattern with the addition of a bubble in the rear and a narrower front response.
This results in a more directional response, slightly better rejection on the sides, and a small area of pick up in the rear. This means that it will not reject sound from the rear as well as a cardioid microphone, but will have a more directional result.
What they are good for:
Hyper-Cardioid mics are great for most of the same things as cardioid mics. They should be used when you need a more directional mic to reject sounds from the sides, but you would like to pick up reflections from the rear.
Figure-8
 Figure-8, (aka Bi-Directional) is pattern that resembles; you guessed it, the number 8. It has equal response on both the front and rear sides of the microphone capsule, with excellent rejection of sound from the sides of the microphone.
This pattern is almost always seen in ribbon microphones, and is commonly an option in multipattern mics.
What are they good for:
Figure-8 is used most commonly in stereo miking techniques such as MS and Blumlein, which both, by definition, involve a figure-8 microphone in some way.
- Figure-8's can be used as room mics.
- To record two sources with a single microphone. For example, two vocalists on opposite sides of the microphone.
- Having the rear side of the capsule may also come in handy for picking up some nice room sound while miking an acoustic instrument.
Omni-directional
 Omnidirectional microphones will pick up sound equally from all sides of the microphone. They tend to have a better low frequency response, as well as, a generally smoother response across the entire frequency spectrum. They also tend to exhibit some directional characteristics at higher frequencies - and you thought that Omni was going to be simple!
What they are good for:
- They are commonly used as room mics.
- You could use an omni pattern when you need to record multiple background singers at the same time, but only have a single mic. (Because they're all being recorded together, there is no way to fix an individual's pitch problems)
- Omni would also be useful inside a piano, there may be nice reflections bouncing off the bottom of the lid that add nicely to your sound.
Bonus Points…
Some mics have multiple patterns and allow you to switch between them! So these mics are versatile and helpful for learning about how different patterns respond.
The best way to learn about polar patterns is to use them, and to look at the frequency response of different polar patterns for your favorite mics. These can usually be found on a microphone company’s website under some type of technical info or specs page for each of their mics.
Also be sure to check out www.microphone-data.com as well. This site has a wealth of information on most of the microphones out there, including pickup patterns.
~AudioBags
Forum Moderator
Sources:
“Sound Reinforcement Handbook” by: G. Davis and R. Jones
“Sound and Recording” by: F. Rumsey and T. McCormick
“Recording The Beatles” by: B. Kehew and K. Ryan
www.microphone-data.com
en.wikipedia.org/wiki/Microphone
www.neumannusa.com
www.rodemicrophones.com
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