Selecting the Right Mic for the Job

First order of business: Get a headset. Plug it into your camcorder. As you record, listen. Is that how you want your video production to sound?

So-called onboard mics take the middle ground. They pick up sound from everywhere, including camera noise and wind. If you zoom in on a subject, onboard mics don't zoom with you. They still pick up noise from all around you. Crowd noise, sound reflecting off walls, the hum from the air conditioner, the zoom lens itself as well as noise you create while handling the camcorder.

What you need are some external mics. Specialized mics that serve narrow but useful functions. I've illustrated them in Figure 7.1. Here are the five basic types:

  • Handheld

  • Lavaliere

  • Shotgun

  • Surface mount

  • Wireless

Figure 7.1. Five standard-issue mics: Handheld, shotgun, wireless handheld, boundary, and lavaliere. (Products provided by Shure, Inc.)

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And, if purchasing some number of these mics has not totally overwhelmed your budget, add a wireless mic setup.

Handheld Mic

If you own only one external mic, make it a handheld. They're the rugged workhorses of the audio industry. Built with internal shock mounts to reduce handling noise, you'll use these mics for interviews, place them on podiums to record speeches, and use them to create narrations.

Many handheld mics are "omnidirectional," meaning they pick up sound from all directions. So they'll pick up ambient room noise as well as close-up audio. To minimize that unwanted noise, keep the mic as close to your subject as practical?about a foot from the speaker's mouth works well.

A top-of-the-line, rugged, durable handheld will cost from $150 to $250. Shure, Inc., the world's leading mic manufacturer, loaned me a handheld?as well as a lavaliere and a shotgun mic?to test while writing this book. (A senior engineer with Shure provided the expert sidebar later in this hour.) The Shure handheld SM63 performed flawlessly within a wide frequency range, accurately capturing low and high voices. It retails for $225.

Most handheld mics use what's called a dynamic transducer. As Figure 7.2 illustrates, the transducer is a thin diaphragm attached to a tiny coil. As sound waves vibrate the diaphragm, the wire moves over a magnet, which converts that physical energy into an electrical signal. Dynamic transducer mics do not require any electrical power to operate.

Figure 7.2. Cutaway views of a dynamic transducer mic (left) and a condenser transducer mic (right). (Illustration courtesy of Shure Inc., 2002.)

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The other type of mic?the condenser transducer, also shown in Figure 7.2?needs so-called "phantom" power provided by a mixer or batteries. It uses a thin, flat plastic or metal diaphragm layered over another piece of metal or metal-coated ceramic. It is typically very small and has an extremely weak signal that requires preamplification before sending it to your camcorder or a mixer.

Lavaliere Mic

Most lavalieres use condenser transducer technology. They're perfect for formal, sit-down interviews. Their tiny size means you can conceal them to minimize that "Oh, we're watching TV" disconnect. The downside is that most require batteries. As you know, batteries invariably can fail at critical moments, so always use fresh, high-quality mic batteries. It is possible to power lavalieres directly from some mixers, but few budding video producers will use mixers.

I tested Shure's WL50B. The clear and crisp sound was a cut above the handheld and is reflected in its higher price: $316.

Shotgun Mic

So-named because it resembles a shotgun barrel, the shotgun mic's "unidirectional" barrel (called an interference tube) narrows the focus of the audio field to about 30 degrees.

A shotgun mic can handle a number of tasks. I picked up one idea from top freelance photojournalist John Alpert. He's a "one-man band" who ventures into uncomfortable and frequently dangerous situations and uses his affable demeanor to get some amazingly revealing sound bites. Instead of shoving a handheld mic into his subjects' faces?which frequently leads to "mic-stare" and other nervous reactions?he uses a shotgun mic tucked under his armpit. He leans his head away from the camera viewfinder and simply chats with his subjects in his unique, "gee-whiz" kind of way. It works like magic.

One thing shotgun mics don't do is zoom. As Chris Lyons, the Shure engineer who wrote the audio expert sidebar says, "They're more like looking through a long tube at someone." They narrow your "view" of the sound.

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The telephoto lens equivalent in the microphone world is a parabolic dish. You've seen networks use them along the sidelines of NFL games to get those great "crunching" hits.


Good shotgun mics will set you back about $1,000. I tried out Shure's superb SM89 ($1,180). This is a condenser mic and needs phantom power that a standard prosumer camcorder cannot provide. A $100 PB 224 portable phantom power adapter from the Rolls Corporation (www.rolls.com) will take care of that.

Boundary or Surface Mount Mics

You'll use these very specialized mics to pick up several speakers at a conference table or on a theatre stage. They are built to be placed on a flat surface and will pick up sound waves in both the air and from the hard surface. A good omnidirectional boundary mic costs about $160.

Wireless Systems

A wireless system is a major purchase that may set you back about as much as a medium-quality DV camcorder. But it can make your life a whole lot simpler and give you some incredible audio.

Wireless mics open a whole new spectrum of possibilities?a presenter at a tradeshow, the priest at a wedding, or a football coach working the sidelines. Wireless mics enable you to grab sound from a distance. Once you use one, you'll wonder how you got along without it. They are a luxury, and good ones are priced to match. My Shure UP4 test unit, including receiver and small body-pack transmitter, retails for $1,638 (see Figure 7.3).

Figure 7.3. The Shure UP4 wireless setup.

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    Part II: Enhancing Your Video
     
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