While all mics essentially pick up the same audio, they don’t all pick up audio the same way. The various types of microphones are designed for specific uses.
To the typical non-golfer, all golf clubs are the same. In fact, it seems a little crazy to carry 10 of them around just to get that little ball into the hole a couple hundred yards away. But expert golfers know that every club has its own unique and very specific purpose. Knowing the potential of each club and how to select the correct one at the correct time is a big part of a professional golfer’s game. In a similar way, microphones may all seem pretty much the same to the uninitiated videographer. They all let you record audio, right? Do you really need more than one?
Knowing the strengths and weaknesses of each mic type will help the savvy shooter choose the right microphone for every job. A big part of this is a simple understanding of the four most common pickup patterns employed by the majority of mics and how they affect your sound quality.
Omnis are multipurpose workhorses. They pick up audio in a circular pattern that allows them to capture audio in all directions (in front, to the sides and behind the mic.) Most all of the microphones built into camcorders are omnidirectional microphones. That’s why operators of consumer camcorders are often heard so clearly on their recordings.
2 - Cardioid/Hypercardoid
Most handheld microphones use cardioid or hypercardioid pickup patterns that record sound waves primarily in the direction the microphone is pointed and from the sides in a heart shaped pattern, without entirely rejecting sound coming from behind the mic. Cardioid mics generally capture audio in a more rounded area in front of the mic, while hypercardioids offer a more elongated range of sensitivity and suppress more sound from the sides than their cardioid cousins.
3 - Bidirectional
If you need to record clear audio to the sides of your mic, but want to supress sound coming from the top and bottom, a bidirectional mic is the choice to make. Mics of this type can be positioned on a table between two interview subjects (think of the big, cool looking mic that sits on David Letterman’s desk), and are often used by artists who record rock music and voice talent in vocal booths.
4 - Unidirectional
Most shotgun mics are highly directional and record audio only in the direction that the barrel of the mic is pointed. They are typically mounted on long boom poles and held over the head of the subject, just outside the visible part of the frame. The long, narrow pickup pattern of unis makes them the mic of choice for producers making films or shows built on actors delivering dialogue. They offer good range, and reject unwanted ambient audio well.
As you shop for your next mic (or mics), remember to pay close attention to its pickup pattern. The shape and appearance of the mic is not always a good indicator of the pickup pattern and performance. The best way to know what you’re getting and to find what you need is to do a little research on the model number. Look for the pickup pattern fields in Videomaker’s microphone reviews and buyer’s guides, and on manufacturer websites. Now, put down that boom pole and hand me my driver. It’s tee time.