| One of the crazy inconsistencies of video creation is that a lens is useful only if it remains connected to its camera body, but a microphone is often more useful when it is not connected to a camera body. Sitting on top of a camcorder, a microphone is susceptible to machine noises and inadvertent sounds that are made by the camera operator and crew. Also, especially indoors, a camera-mounted microphone tends to be subject to reflective sounds. So you probably don't want to rely on your camcorder's built-in mic. Omnidirectional, unidirectional, and shotgun microphones Keep the following classifications of microphones in mind for your videography needs: - Omnidirectional — a microphone for all directions: Omnidirectional microphones pick up sound from all directions. These microphones are typically used when you are confident that all the sound sources within an immediate proximity to the microphone are desirable. Your camcorder's factory-supplied microphone is probably omnidirectional. Omnidirectional microphones can cost as little as $29 or can cost hundreds of dollars.
- Unidirectional — a one-person-at-a-time microphone: Just the opposite of the omnidirectional type, a unidirectional microphone collects sound only from the area that's directly in front of it. Unidirectional microphones are especially helpful where you have more than one person wearing a microphone and you need to independently control the volume of each person. They are also useful in situations where you need to isolate one sound from a bunch of unwanted sounds. Unidirectional microphones also can cost as little as $29 or can cost hundreds of dollars.
- Shotgun — a long-range microphone: The term shotgun microphone may imply that it is a roaming and haphazard microphone. A shotgun microphone is just the opposite. You use it for pinpoint isolation of sound. Typically, you use shotgun microphones when you cannot place a microphone directly in front of a person on-camera. A crew member stands off-camera and directs the shotgun microphone at the person who is speaking. The shotgun microphone picks up sound only from where it is aimed. Basic shotgun microphones start at around $39 but can cost $1,000 or more.
In Figure 1, note that the room causes a multiplication of audio sources, that is, the camcorder's audio recorder is faithfully recording what it is receiving from the microphone. However, the omnidirectional camcorder microphone shown in Figure 1 is receiving the sum of all the sounds in the immediate environment — not just the speaker's voice. One way to put your microphone on a "sound diet" is by modifying or controlling the sound environment around the microphone.
Figure 1: A microphone doesn't know what sound to identify as the correct one, so it collects and assigns equal priority to all sounds.
Lavalier and handheld microphones When you're recording weddings, training, or any other kind of video where the quality of the audio reproduction is important, you should invest in a decent lavalier microphone. A lavalier microphone is a small microphone that can be clipped to a necktie or blouse (see Figure 2). Hiding a lavalier microphone is easier than hiding a handheld microphone, but the handheld variety is more versatile. Although lavaliers are usually omnidirectional, you can buy unidirectional ones, which are typically used for recording musical instruments.
Figure 2: Two types of microphones.
You may also want a handheld microphone. Handheld microphones aren't always handheld (they're often on microphone stands), but that's not really important. Like lavaliers, most handheld microphones are omnidirectional. Wired and wireless microphones Based on your budget and your recording needs, you can use a wireless microphone, transmitter, and receiver or a hard-wired microphone, which is a microphone that's connected to a long cable. You have a microphone, and the microphone is connected to the recorder by a long audio cable — in some instances, a very long cable. A decent wireless microphone system typically costs $400–$500. You can find wireless microphone systems that cost less than this, but you'll have difficulty finding a system with a receiver small enough to fit on a digital camcorder for less than $400.  | When you're buying a camcorder, double-check that it has a connector for an external microphone. And while you're at it, make sure that a headphone jack is included, too. Most digital camcorders have external headphone and microphone jacks, but these are good things to confirm nonetheless. The headphone jack is good for listening to sound levels. |
Hard-wired systems are inexpensive and dependable. Just plug one end of the cord into the microphone and the other into the recording device. Like wireless systems, wired systems also have limitations. Following are some limitations: - Dragging the cord around on the floor causes it to accumulate dirt, which could result in equipment damage or signal distortion.
- Hiding the wiring when recording can be problematic.
- You may pick up a low hum if you inadvertently run audio wiring in a parallel path with electrical wiring.
Wireless systems combat some of the wired system's problems but have limitations of their own, as follows: - They have a never-ending demand for fresh batteries.
- The transmitter is hard to hide on clothing.
- Radio interference is occasionally possible.
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