The Macintosh iLife 06

Upgrade Your Microphone

To get better sound, get a high-quality external microphone and place it close to your subject.

Before you buy an external mike, determine whether your camcorder can accept one. Some inexpensive camcorders don't provide a jack for an external mike; others may require an adapter that connects to the bottom of the camera. Most mid-range and all high-end camcorders have external mike jacks. On most cameras, it's a 1/8-inch stereo minijack.

Clip-on. Microphones come in all sizes and designs. Some are specializedfor example, a lavaliere mike, which clips to a lapel or shirt, is great for recording a single voice, such as that of a teacher (or TV host). But a lav mike is unsuitable for recording a musical performance.

Shotgun approach. When you can't get the mike close to your subject but still want to reduce extraneous noise, consider a shotgun mike. In a shotgun mike, the microphone capsule is mounted within a long barrel designed to reject sound coming from the side of the mike. Shotgun mikes are popular in TV news and movie making. They're sensitive enough to be located out of the video frame, and their highly directional sensitivity means they won't pick up noise from cameras and crew members.

A shotgun mike works best when mounted on a boom, a long pole (often hand-held) that allows the mike to point down at the subject. When you see a video crew with one person who appears to be holding a fishing pole with a long tube on the end of it, you're seeing a shotgun mike (and a sound technician) in action.

Two in one. The most versatile mike you can buy is a single-point stereo mike. A stereo mike crams two microphone capsules into a single package. Each capsule is precisely positioned relative to its companion, thus eliminating one of the biggest challenges of stereo recording: getting accurate balance and separation between the left and right channels. I use the AT822 from Audio-Technica (www.audio-technica.com).

With high-quality extension cables, the mike and camera can be up to about 25 feet apart. At greater distances, you risk losing some high frequencies and picking up hum and other electrical noise.

A balanced alternative. When you need to run cables longer than 25 feet or soor when you want the best possible quality and are prepared to pay for itconsider a balanced mike. All of the aforementioned mikes are available in balanced and unbalanced versions. A balanced mike is wired in a way that reduces electrical noise and allows for cable runs of up to 100 feet or so. Balanced mikes cost more than unbalanced ones, but professionals and serious amateurs prefer balanced mikes due to their resistance to electrical noise and their support for longer cable runs.

A balanced mike typically uses an XLR connector, and only high-end camcorders have XLR jacks. But there is a way to connect a balanced mike to an unbalanced miniplug jack: the DXA-2 adaptor from BeachTek (www.beachtek.com). A compact metal box that attaches to your camera's tripod mount, the DXA-2 requires no external power supply and has built-in knobs for adjusting volume levels.

Placement is Everything

To do justice to any mike, position it properly. For that school play or recital, use a mike stand and position the mike high, pointing down toward the stage at about a 45-degree angle. If you can't set up your own mike stand, just try to get the mike at least a few feet off the stage and as close to center stage as possible.

How close should the mike be? That depends on what you're recording (see the table at right). The closer the mike is to a sound source, the less room noise and reverberation it picks up.

But if the mike is too close, stereo separation is exaggeratedsome sounds come only from the left speaker, others only from the right, and sounds in the center are louder than they should be. Move the mike too far away, and you get a muddy-sounding recording with too much room reverb.

When recording a live performance, try to show up for rehearsals so that you have time to experiment with different mike distances. If your camera has a headphone jack, connect a good pair of headphonesones whose cups surround your ears and thus block out external sounds. Record a test, play it back, and listen.

For recording narrations, consider assembling a makeshift sound booth that will absorb room echo and block computer and hard drive noise. Glue some sound-absorbing acoustical foam onto two sheets of plywood or foamcore. (See www.soundsuckers.com for a wide selection.) Position the two sheets in front of you in a V shape, with the mike at the narrow end. If you're on a tight budget, use blankets, pillows, carpet remnants, or even a coat closet. The idea is to surround yourself, and the mike, with sound-absorbing material.

Another major microphone manufacturer, Shure, has published some excellent mike-placement tutorials. Download them at www.shure.com/booklets.

Creating an Audio Bed

If you weren't able to get good audio when you originally shot your video, consider muting your video's audio track and just putting a music bed behind your shots. Create a montage of shots, using bookmarks and direct trimming to help you time your edits to the music.

And finally, a related tip: If you're shooting scenes where the audio is mostly ambient soundthe waves at the beach, the din of a partyshoot a few minutes of uninterrupted video, keeping the camera stationary. After importing the video, delete the video track and keep the audio. (In iMovie HD, drag the video clip to the timeline, then choose Extract Audio from the Advanced menu.) Now you have an audio bed upon which you can put a series of video shots. After you add those shots, mute their audio. This technique eliminates jarring sound changes between shots.