Sound Track: External Miking (page 2)

Though not a mike type per se, the boom mike is a staple of video production. A boom is nothing more than a long pole designed to hold a mike near the action but outside the camcorder's view. Good boom poles change length easily, have clips to hold a cable and elastic bands to isolate the mike from shocks. Workable booms may have a fixed length pole, dowel or broom handle, no clips and plenty of gaffer's tape to hold the mike.

In other words, a boom doesn't have to be pretty or expensive to work. It simply needs to allow a boom operator (also called a "volunteer") to hold the mike as close to the subject as possible without ending up on-screen. In addition to the broom handle, functional booms include a mike stand with its base removed, a billiards cue, a heavy fishing pole, a closet hanger rod or dowel and a shower curtain pole to name a few. The list of suitable boom poles is as long as the guerilla videographer's creativity.

In most cases, a directional handheld or instrument mike is the best choice for boom use. You can use a shotgun mike on a boom (more on this later), or even a lavalier taped to the end of the boom. Remember, good miking is not about what you have, it's about where you put it.

The shotgun mike got its name because of its long, lethal-looking interference tube. This tube tries to cancel out any sound not coming from directly in front of the mike. Though not nearly as directional as it looks, the shotgun mike is as close to an audio "zoom lens" as we can get.

Traditionally, the shotgun mike is used within 10 feet or so of its subject. As with any type of mike, the shotgun mike sounds better the closer it is to its subject (within reason). Hang a shotgun mike on a boom, and you can get great audio from even moderately noisy shooting locations.

Mounting a shotgun mike on a camcorder usually results in little or no sonic improvement. The reason is simple--the camcorder tends to end up too far from the subject to get crisp audio, even with a 12-inch shotgun mike attached.

A great place for the shotgun mike is mounted in a mike stand just outside the frame. Point it in at your subject(s) from a few feet away, and you'll enjoy audio almost as powerful as that from lavalier or handheld mikes.

The last type of external mike we'll cover is the boundary layer microphone. This type of mike suspends a small mike element just above a large, flat plate. Any sound coming from the mike side of that plate is fair game, giving the boundary mike a hemispherical (half-sphere) pickup pattern. Any flat surface the boundary mike lays on becomes part of the boundary and fills out the sound.

In practice, the boundary mike's pickup pattern is wide enough to be considered omnidirectional. This means you can forget this mike type when there's any noise competing with your subject.

The boundary mike excels where you want to pick up general, ambient sounds or the voices from a number of people engaged in conversation. Placed in the middle of a boardroom table, the boundary mike will pick up every voice equally. Float a boundary mike on a thin layer of foam and place it on the edge of a stage to pick up a play or recital. Lay it on the ground near a tailgate party to pick up every laugh, jeer and bad joke.

Outfitting your video rig with an external mike or two isn't difficult or expensive. In almost every case listed above, you can get a quality mike for less than $100.

And when you hear the improvement one crisp C-note will make in your audio, it will sound like a million bucks.

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