074 – Polar Patterns
Being aware of a microphone polar pattern can help you control what gets in (or stays out of) your mix.
Written by Scott Adamson
A polar pattern indicates the sensitivity with which a microphone picks up sound from various directions. This pattern is displayed in graphical form. For our purposes in live sound, we most often use cardioid and supercardioid patterns, but there are several others, as well.
I discuss more in this video from our Live Sound Essentials course:
Mics with a cardioid polar pattern pick up sound fully in the front, but reject sound arriving from the back. As you move from front to back, sound will still be picked up on the sides, but to a lesser degree than in the front. Like cardioid, mics with a supercardioid polar pattern pick up sound “normally” in the front, but also pick up a small amount from behind. The sound is significantly cut from the sides, making it a tighter, more focused pattern.
Think about the difference between Shure’s SM58 and Beta58 mics. The SM has a cardioid polar pattern while the Beta has a supercardioid. These mics do have slightly different sonic characteristics, but the polar pattern is also an important consideration when deciding which one to use.
Let’s consider stage wedges. Sometimes we need them to be really loud. Though we mainly control feedback through EQ, polar pattern and physical placement of the wedges are key factors, as well. If you’re only using one wedge, you might run into feedback problems with a supercardioid mic, due to the way it narrowly picks up sound from the back. Instead, by using two wedges and spacing them out, you can create a dead zone behind the mic. Though not a hard and fast rule, using a cardioid mic, which rejects sound from the back, with a single wedge can make it a bit easier to quell feedback at especially loud volumes.
Using a mic with a tighter pattern can also reduce the amount of unwanted stage noise that’s picked up in a particular channel. When working with an especially quiet vocalist, for example, you’ll need to set the mic gain at a higher level. This means you’re not only boosting the level of the singer, but the rest of the noise on stage, as well. A more focused polar pattern will offer better rejection from outside sound sources.
Remember that some mics give you options! On many condensers, you’ll find a switch that allows you to choose between three, four or even five polar patterns. The best pattern for you is ultimately a personal choice based on the needs of the artist you’re mixing.
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In addition to cardioid and supercardioid, some mics have a hypercardioid polar pattern, which works very similarly to supercardioid. We also come across omnidirectional mics, though we often just call them “omni.” These mics pick up sound equally from all sides, which often isn’t practical in live sound. Not only will they pick up sound from all directions on stage, they’ll also pick up sound from wedges, main speakers and the audience. Finally, we have bidirectional mics, also called figure 8, based on the shape of their polar pattern. These mics pick up sound equally from the front and the back, but not the sides. Ribbon mics are bidirectional by design, with the exception of a few modern innovations like the hypercardioid Beyerdynamic M160.
Remember that some mics give you options! On many condensers, you’ll find a switch that allows you to choose between three, four or even five polar patterns. The best pattern for you is ultimately a personal choice based on the needs of the artist you’re mixing.
