Sound Advice: Captured in Time

You’ve wrapped up the shoot on your latest masterpiece. The visuals are stunning and the camera work will win awards. Now comes the painful, but necessary process of capturing the footage to edit in your computer.

Over the past few years, thousands of budding videographers bought analog capture cards. Many of these cards produce excellent-quality video, so what’s the rush to switch to digital? During your upcoming capture session, there are several things you can do to optimize the audio quality through your analog capture card. Tacky audio can spoil all the time you’ve invested in the image, turning even the most lavish production into a huge waste of time. Not to worry, dear reader; all is not lost. We can fix it.

Do Your Homework

We’ve said it before and we’ll say it again — record the audio right in the first place. Video editing software gives you the ability to work audio miracles in seconds, but there is no substitute for recording the audio properly at the shoot. Some simple attention to detail will yield great rewards when it’s finally time to capture.

Scout the location before the shoot, listening for noises or acoustical problems that could harm your audio. If shooting outdoors, listen for traffic noises, trains or airplanes. Some birds singing in the background might be nice, but the neighbor’s lawn mower will be hard to work around.

Microphone selection is also important. Shotguns are probably the most versatile microphones for videographers. Although normally used overhead, just out of the video frame, a shotgun mike is also useful as a hand-held in high-noise environments. If you use a lapel mike outside, carry a foam windscreen and, if possible, face talent so their bodies block the wind.

Headphones are simple items, but they are invaluable to the video shooter. Plug in a good pair and monitor the audio while recording. They can help isolate hums and buzzes along with the occasional dead microphone battery.

Spend a few minutes and set up your entire rig, checking for potential problems and equipment failures. It’s better to know about trouble while you can still fix it — not out in the field and on the clock.

Houston, We Have Capture

You’ve completed the shoot and it’s time to settle into your edit suite, capture that awesome footage and build your prize-winning program. Using an analog capture card can be as much art as it is science and there are many potential pitfalls.

If you have an external audio mixer, consider pre-conditioning your audio before it enters the capture card. Just feed the audio outputs from your source deck (or camcorder) to the inputs on the mixer, and then route the output of the mixer to the audio inputs on your capture card. This gives you the ability to easily correct audio volume differences in various takes of the same scene. If your mixer has tone (equalization) controls, you can also reshape the sound quality to minimize wind noise or emphasize a weak voice. Of course, you can do much of this with your video editing software, but pre-conditioning eliminates extra steps and render time.

Once you’ve routed the audio into the capture card, check the input levels. It is often the case with Windows computers that recording level problems (or even no audio at all) can only be resolved by accessing the Windows Recording Control panel. You can frequently find this by double-clicking the speaker icon on the taskbar. Too much level will cause permanent distortion of your audio; there is no way to filter it out after the fact. On the other hand, too little level will likely introduce noise or hiss into your audio. It’s possible to filter out some of this, but it’s better to record with the proper level. Many third-party capture utilities offer volume-level meters, which are the only accurate way to set the gain to gauge your input (Pinnacle’s system for its DC30+ is excellent). Alternatively, many audio editing packages also offer input-level meters. Just check their Preferences or Options menus to select your capture card as the audio source.

Most likely, the cables you use to route audio into your capture card are unbalanced cables and subject to noise pickup from external sources. If this happens, you’ll hear a faint (or not-so-faint) hum or buzz in the captured audio. Eliminating the problem is fairly easy. Keep your source deck (camcorder) and cables away from computer monitors and power supplies. Cheap AC/DC conversion boxes that plug into electrical outlets are famous for producing audio hum. If you must mix power and audio cables, keep the intersections perpendicular rather than parallel. This will minimize the interference. Stay off your cell phone during capture sessions. The RF radiation from the phone can cause problems with your audio recordings. Also, certain computer screens emit a field that causes a buzz in some audio signals. This can occur with hand-held computers and even the flip-out LCD on your video camera. Sometimes, changing the refresh rate on the monitor can help.

The Digital Divide

If you use FireWire for your video captures, you may believe there is nothing you can do to affect the quality of audio until after it lives inside your computer. While that may be true for your digital footage, you can use your FireWire-enabled camcorder as a digital gateway for older VHS tapes and other audio sources.

At some point, you’ll need to capture audio from a non-digital source such as a CD player, MiniDisc or maybe even a musical instrument. Many digital camcorders offer a pass-through option that allows you to connect analog audio and video signals, then output through FireWire to your computer. This is a great way to apply some of the techniques we’ve discussed to other audio signals, even narration.

Fade Away

As usual, some attention to detail produces a remarkable improvement in the quality of your audio. Use these tips on your next production and squeeze a few more miles out of that analog capture card.

[Sidebar: Rip it Good]
How do you get audio from a music library CD into your computer? Consider a freeware program called CDex (www.cdex.n3.net). After a simple setup, click the track you want from the main screen, and then click the WAV button. CDex rips the CD track to your hard drive in WAV format — perfect for further editing or dropping into your production. Alternatively, many of the MP3 players like WinAmp and MusicMatch Jukebox include a similar feature. Whatever method you choose, you’ll have a clean digital copy of the music minus the potential noise of analog recording.

[Sidebar: Never Assume]
Recently, I had to capture some footage from a VHS tape. Once I started the capture, the left channel mysteriously had no volume. I checked everything — the volume and pan controls for my capture card, hardware preferences, even the software itself. Everything was fine but still no left channel. After some serious head scratching, I discovered the audio hookup cable was broken. I’d used it the day before with no problem, but sometime during the night, it went bad. Time-honored troubleshooting principle: never assume anything. Unlike our legal system, where you are presumed innocent until proven guilty, troubleshooting starts with the idea that everything is suspect; testing identifies the working parts.

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