Sound Track: Sounds of the Wild

When it comes to capturing great audio, you've probably heard about the challenges of shooting indoors - troublesome acoustics, unwanted noises, etc. But what about the outdoors? Does freeing your camcorder from enclosed spaces spell the end of audio troubles?
Not at all. There may be more pitfalls awaiting the unwary videographer outside the sanctity of four walls. It�¯�¿�½s a tough world out there, one where you have to use your head, and your ears, to capture great audio.

A Vast Expanse

If there�¯�¿�½s one thing you can say about the great outdoors, it�¯�¿�½s that they�¯�¿�½re big. In most cases, you�¯�¿�½ll have all the room you need to set up any kind of shot. You can use that long zoom lens to put hundreds of feet between you and your subject. That�¯�¿�½s fine, provided you don�¯�¿�½t plan on getting any usable audio from such a shot. The heady spaciousness of the outdoors encourages shooters to flaunt the number-one rule of audio, which is to get the mike close to the subject. The closer the mike is to the subject, the more crisp, powerful and up-front the resulting audio will be.
Indoors, sounds careen off walls and other surfaces to create reflected sound or "reverb." A distant mike placement means the sound coming directly from your subject (the sound you want) is competing with all this reflected sound. Moving the mike closer to the subject increases the volume of the direct sound relative to the reflected sound, and puts an end to distant and indistinct audio.
Those of you who know your sound waves are probably saying, "Wait a minute, there's no reflected sound outdoors!" Right you are. But mike-to-subject distance is still your greatest enemy, just like when shooting indoors.
Outdoors, direct sound isn�¯�¿�½t competing with bouncing sound, it's competing with other unwanted noises. As your camcorder gets more than a few feet from the subject, its mike starts picking up such noises as a jet overhead, a lawnmower three houses down or Jethro Tull on the radio with as much intensity as the desired sound.
Even if you are far from roads, houses and oldies radio, unwanted noises are a problem. Most camcorders, when presented with near-silence, get bored and begin recording themselves. Hence, your camcorder�¯�¿�½s built-in mike may start picking up the whir and hum of motors from within its own case, or the sound of your fingers pressing buttons. The farther you are from your subject, the more inclined your camcorder will be to create its own soundtrack.
Too great a distance between mike and subject impacts your sound in another way. As sounds move through the air, higher frequencies dissipate and scatter as a function of distance. This means the further you get from your subject, the more dull and low-fi it sounds. The crisp, articulate high frequencies you pick up a few feet from a speaking subject are pretty much gone by 20 feet. At 100 feet, youÃ�¯Ã�¿Ã�½re getting sound more like that of an AM radio or telephone. This is another principle that makes distant subjects sound, well, distant.<…