Mic Check!
Posted by Keith · April 15th, 2008
There’s nothing I enjoy more than the sound of my own voice. Ahh, the soothing baritone, the melodic timbre. And the love I hold for my seraphic vocalizations is only increased by one thing, amplification!
That’s right, we’re talking microphones today. You’ve all seen them. You are acquainted with their shape and function. You may have even mentally transformed the handle of your hairbrush into one for a brief, bathroom rendition of “I Will Survive”. But how well do you understand the complexity of the microphone’s inner-workings or, more importantly, the different makes and models? I’m going to go ahead and guess not well, so I’ll attempt to educate.
(**Note - This is a cursory explanation, the science of microphones is a detailed and complex discipline, of which I know only the superficial details.)
There are basically two different categories of mics: dynamic and condenser. The subcategories for these two branch off into several winding directions, but the main distinction between the classifications are that condenser mics require electronic power while dynamic mics do not.
Dynamic microphones use either moving coils or corrugated metal ribbons suspended in magnetic fields to produce sound waves that are sent down a cable to an amplifier. It’s all very complicated and quite outside my understanding, but dynamic mics are generally more robust and less expensive than condenser mics. Because they require no electrical charge, they are water resistant and are generally the type of mic you’ll see on in the hand of a singer or speaker on stage.
Condenser mics produce electrically charged signals, which make the mics much more sensitive and powerful instruments. They are usually quite delicate and can range from cheap throw-away mics to high fidelity equipment. Because they allow for heightened sound sensitivity, they are the preferred mic for studio recordings and film production. For their power, they require either an on-board battery or what is called phantom power, which simply means that the power is derived from a third-party source, like the recording camera.
Aside from the above distinctions, mics can also be classified by their recording pattern. Different mics pick up sounds from different directions, the following details the categories with their corresponding diagrams:
(In the illustrations, the mic is located at the center of the circle with the pick-up pointed north. The protruding bubble represents the wave pattern captured by the mic. You’ll note that many mics have a smaller bubble emanating from the behind the pick-up, meaning that sounds may register even if the mic is pointed away from their source.)
Omnidirectional: Records indiscriminately in all directions.
Cardioid: The most prevalent uni-directional mic. Named for it’s heart-shaped pick-up pattern.
Super Cardioid: Similar directionality to a cardioid but more shallow.
Bi-Directional: Records in two directions but limits sound pick-up from the sides.
Shotgun: Super directional, picks up almost no sound that is not directly in front of its receiver.
There are also different, application-specific microphone designs, few of which are noteworthy here, save the ever-popular lavaliere (or lav) mic. This is simply a very small condenser microphone, usually accompanied by portable battery-pack, that may be pinned to one’s clothes and then concealed. This is used often in film production, theater, live television, or any instance when a mic must be close but hidden.
There is much more information one may discuss on the topic of mics, but the above should be a good start for the novice. If you take nothing else from this lesson, please realize that there are more options available than the puny sound holes drilled into the front of your handheld camera. Quality audio is paramount to professional video production. Audiences will accept lesser quality images, but poor sound is unforgivable.
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Tags: Mics | Posted in Video Production and Publishing |
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