2.4. Replace the Microphone The built-in microphone on your camcorder can't be beat for convenience. It's always there, it's always on, and it's always pointing at what you're filming . Unfortunately, camcorder microphones have several disadvantages. For example: -
They're usually mounted right on the camera body. In quiet scenes, they can pick up the sound of the camcorder itselfa quiet grinding of the electronic motor, or the sound of the lens zooming and focusing. -
If your subject is farther than a few feet away, the sound is much too faint. The powerful zoom lens on modern camcorders exaggerates this problem. If your subject is 50 feet away, the zoom may make it look as though you're right up close, but the sound still has to come from 50 feet away. FREQUENTLY ASKED QUESTION
Automatic Gain Control | | Where's the recording-volume knob on my camcorder ? There isn't one. Modern consumer camcorders use something called automatic gain control (AGC). They set the volume level automatically as you record. That may sound like a neat feature, but it drives professionals nutty. AGC, in essence, strives to record all sound at exactly the same level. When something is very loud, the AGC circuit quiets it down to middle volume; when something is very soft, the AGC circuit boosts it to middle volume. Over the years , automatic-gain circuitry has dramatically improved. The electronic boosting or quieting is smoother and less noticeable than it once was. Even some modern camcorders, however, sometimes exhibit the unpleasant side effects of AGC circuitry : Try filming something that's very quiet, and then suddenly clap right next to the microphone. On lesser camcorders, when you play the footage back, you'll hear how the sudden, loud sound made the AGC back off, cutting the volume way down in anticipation of further loud noises. It takes the camcorder several seconds to realize that the surrounding sound is still quiet (and to boost the volume level back up where it had been). Fortunately, that sudden-adjustment syndrome is a rare and usually harmless occurrence. For most purposes, camcorders do an excellent job of setting their own volume level (although it certainly evens out the dynamic highs and lows of, say, a symphony performance). Besides, you don't have much of an alternative. Only a few, more expensive camcorders permit you to override the AGC circuit (and adjust the sound level manually). Even if you plug in an external microphone, most camcorders take it upon themselves to adjust the sound level automatically. |
"Camcorder sound," that hollow, faraway sonic quality present on most home videos (including the ones shown on your cable station's public-access channel late at night), is one of the most obvious differences between amateur video and professional work. Even if viewers can't quite put their finger on how they know that something was shot with a camcorder, they'll know that it was shot with a camcorder just by listening. 2.4.1. Clip-on (Lavalier) Microphones Few camcorder accessories, therefore, are more useful than an external microphone. And it doesn't have to cost a lot. For $20, Radio Shack will sell you a high-quality tie-clip microphone like the one on the lapels of newscasters (see Figure 2-2). Figure 2-2. A tie-clip microphone, known in the business as a Lavalier mike ("lava-LEER"), is a very inexpensive way to dramatically improve the audio on your footage, especially when accompanied by an extension cable or two. You plug it into the Mic In jack on the side of almost every DV camcorder. (This jack may be concealed by a protective plastic cap.). 
Of course, if the problem of camcorder audio is that it gets worse when the subject is far away, an external microphone with a six- foot cord isn't of much use. Therefore, consider buying a couple of extension cords for your microphone; they come in lengths of 20 feet or more, and cost about $10. You can plug one into the next, using standard miniplug connectors (like the ones on the end of Walkman headphones).
Tip: In certain situations, plugging one cable into the next, as you do when connecting an external microphone to an extension cable, can introduce a hum on your soundtrack. To avoid ruining otherwise great footage, carry with you a pair of cheap Walkman headphones. Whenever you're using an external microphone, plug these headphones into the headphone jack on your camcorder and listen as you film. (In fact, you're wise to use headphones anytime you're filming.)If a humming or buzzing does arise, try exchanging cables, eliminating extension cords, and running the camcorder on battery instead of AC power, until you've isolated the source of the problem.
2.4.2. Wireless Mikes One of those inexpensive tie-clip microphones is ideal when you're filming interviews, speeches, or scripted dialog with actors. But in other situations, a cabled microphone like this is impractical , such as when you're shooting a jogger, somebody in a car, or an undercover agent. For those circumstances, consider buying or renting a wireless microphone. These microphones come in two parts : the microphone held or worn by the actor or speaker, and a receiver that clips onto your camcorder and plugs into the Mic In jack. The receiver picks up the sound signal that's transmitted by radio waves. (Here again, be aware of interference. As you film, wear Walkman headphones to monitor the incoming sound. There's nothing worse than tender words of love being drowned out by a nearby trucker cursing on his overamplified CB radio that's picked up by your receiver.) BUYERS' GUIDE
How to Buy a Microphone | | When you shop for an add-on mike for your camcorder, you'll have to choose between models based on three important microphone characteristics: its technology ( dynamic vs. condenser), its pickup pattern , and its connector . Dynamic microphones sense changes in air pressure caused by sound waves. They use relatively simple technology that's usually rugged, but not very sensitive to quiet sounds. These are the least expensive microphones. A condenser mike (also called electret condenser ), on the other hand, has a built-in amplifier , making it much more sensitive to both sound levels and frequency. These microphones require extra power; some use batteries; some can get their power from the cable that plugs into your camcorder using what's called "phantom power." The important thing to remember when using a condenser mike is to carry spare batteries, because the microphone may go dead at any time during shooting. These mikes are also more expensive and less rugged than dynamic models. The pickup pattern refers to the area in space from which a particular microphone picks up sounds. For example, omnidirectional mikes pick up sound from every sidein front, to the side, from behind. They're great if you need to record groups of people or general environmental sounds, but they pick up too much ambient noise when you're trying to record dialog in a noisy environment. Cardioid microphones block sound from behind, and dampen sound coming from the sides. In other words, they mostly capture sounds they're pointed at, but still pick up some general surrounding sound. This is the most common type used in Hollywood productions . Supercardioid microphones, such as shotgun mikes, are extremely directional. They must point straight at the subject, or they may not pick up its sound at all. These specialized mikes are great in noisy environments, but they're expensive. They usually require an operator, someone who does nothing but point the mike at the sound's source. Finally, consider the connector at the end of the microphone cable. XLR is the professional connection: a big, round, three-pin jack that doesn't fit any camcorder under $4,000. Instead, your camcorder probably accepts eighth -inch, miniphono plugs, which look like the end of a pair of Walkman headphones. Several companies manufacture XLR to eighth-inch adapters, which let you use professional mikes on less expensive camcorders. These converters also have one or two extra jacks , so that you can plug in a second microphone, when necessarya great feature for interviews. Such converters usually include signal-level control knobs , too, that let you manually adjust the sound volume as you're recording. |
2.4.3. Other Microphones If you're shooting documentary -style, it's impractical to attach any kind of microphone to the people you're filming. Depending on how serious you are about your filming, you have alternatives. A shotgun mike is elongated and thin; it's designed to pick up a distant sound source with pinpoint accuracy. (In Hollywood thrillers, shotgun mikes appear onscreen in the hands of the characters almost as often as they do behind the scenes.) Semi-pro camcorders like the Canon XL1 and the Sony VX2000 have shotgun mikes built right in. Clip-on shotgun mikes are available for less expensive Canon and Sony camcorders, too. There's also the boom mike , which requires a helper to hold over the head of the actor on a long poleanother staple of professional film production. Unfortunately, this kind of mike, too, is likely to dampen your spontaneity. 2.4.4. Where to Buy Them You won't find these fancier microphone types, which cost $100 or more, in the local Radio Shack. Online, however, they're everywhere. Video-supply companies like www.rentgear.com, www.markertek.com, and www.bhphotovideo.comare good starting points for your shopping quest. For good information about microphones in general, visit www.audiotechnica.com/using/mphones/guide.  |
