Audio Recording Basic Tips

At some point, you’ll probably want to record some narration or other sound to go along with your movie project. Recording great-quality audio is no simple matter. Professional recording studios spend thousands or even millions of dollars to set up acoustically superior sound rooms. I’m guessing you don’t have that kind of budgetary firepower handy, but if you’re recording your own sound, you can get nearly pro-sounding results if you follow these basic tips:

• Use an external microphone whenever possible. The built-in microphones in modern camcorders have improved greatly in recent years, but they still present problems. They often record undesired ambient sound near the camcorder (such as audience members) or even mechanical sound from the camcorder’s tape drive. If possible, connect an external microphone to the camcorder’s mic input.
• Eliminate unwanted noise sources. If you must use the camcorder’s built-in mic, be aware of your movements and other things that can cause loud, distracting noises on tape. Problem items can include a loose lens cap banging around, your finger rubbing against the mic, wind blowing across the mic, and the swish-swish of those nylon workout pants you wore this morning.
• Control ambient noise. True silence is a very rare thing in modern life. Before you start recording audio, carefully observe various sources of noise. These could include your neighbor’s lawn mower, someone watching TV in another room, extra computers, and even the heating duct from your furnace or air conditioner. Noise from any (or all) of these things can reduce the quality of your recording.
• Try to minimize sound reflection. Audio waves reflect off any hard surface, which can cause echoing in a recording. Cover the walls, floor, and other hard surfaces with blankets to reduce sound reflection.
• Obtain and use a high-quality microphone. A good mic isn’t cheap, but it can make a huge difference in recording quality.
• Watch for trip hazards! In your haste to record great sound, don’t forget that your microphone cables can become a hazard on-scene. Not only is this a safety hazard to anyone walking by, but if someone snags a cable, your equipment could be damaged as well. If necessary, bring along some duct tape to temporarily cover cables that run across the floor.

The easiest way to record audio is with a microphone connected to your computer, although some computers can make a lot of noise with their whirring hard disks, spinning fans, and buzzing monitors. The following sections show you how to record audio using a microphone connected to the microphone jack on your computer.

Delving into bit depth

Another term you’ll hear bandied about in audio editing is bit depth. The quality of a digital audio recording is affected by the number of samples per second, as well as by how much information each sample contains. The amount of information that can be recorded per sample is the bit depth. More bits per sample mean more information — and generally richer sound. Many digital recorders and camcorders offer a choice between 12-bit and 16-bit audio; choose the 16-bit setting whenever possible. For some reason, many digital camcorders come from the factory set to record 12-bit audio. There is no advantage to using the lower setting, so always check your camcorder’s documentation and adjust the audio-recording bit depth up to 16-bit if it isn’t there already.

Understanding sampling rates

For over a century, humans have been using analog devices (ranging from wax cylinders to magnetic tapes) to record sound waves. As with video, digital audio recordings are all the rage today. Because a digital recording can only contain specific values, it can only approximate a continuous wave of sound; a digital recording device must “sample” a sound many times per second; the more samples per second, the more closely the recording can approximate the live sound (although a digital approximation of a “wave” actually looks more like the stairs on an Aztec pyramid). The number of samples per second is called the sampling rate. As you might expect, a higher sampling rate provides better recording quality. CD audio typically has a sampling rate of 44.1 kHz — that’s 44,100 samples per second — and most digital camcorders can record at a sampling rate of 48kHz. You will work with sampling rate when you adjust the settings on your camcorder, import audio into your computer, and export movie projects when they’re done.

Understanding Audio

Consider how audio affects the feel of a video program. Honking car horns on a busy street; crashing surf and calling seagulls at a beach; a howling wolf on the moors — these sounds help us identify a place as quickly as our eyes can, if not quicker. If a picture is worth a thousand words, sometimes a sound in your movie is worth a thousand pictures.
What is audio? Well, if I check my notes from high-school science class, I get the impression that audio is produced by sound waves moving through the air. Human beings hear those sound waves such as condolence phrases being told, they make our eardrums vibrate. The speed at which a sound makes the eardrum vibrate is the frequency. Frequency is measured in kilohertz (kHz), and one kHz equals one thousand vibrations per second. (You could say it really hertz when your eardrums vibrate . . . get it?) A lower-frequency sound is perceived as a lower pitch or tone, and a higher-frequency sound is perceived as a high pitch or tone. The volume or intensity of audio is measured in decibels (dB).

Capturing your video

Once all your settings are, uh, set, you’re ready to start capturing. (Finally!) I recommend that you rewind the tape in your VCR or camcorder to at least 15 seconds before the point at which you want to begin capturing. Then follow these steps:

1. Click the Start Capture button at the bottom of the Studio capture window. The Capture Video dialog box appears.
2. Enter a descriptive name for the capture.
3. If you want to automatically stop capturing after a certain period of time, enter the maximum number of minutes and seconds for the capture.
4. Press Play on the VCR or camcorder.
5. Click Start Capture within the Capture Video dialog box. The capture process begins, and you’ll notice that the green Start Capture button changes to the red Stop Capture button. As Studio captures your video, keep an eye on the Frames Dropped field under the preview window. If any frames are dropped, try to determine the cause and then recapture the video. Common causes of dropped frames include programs running in the background, power saver modes, or a hard disk that hasn’t been defragmented recently.
6. Click Stop Capture when you’re done capturing.

Studio reviews the video that has been captured and improves scene detection if possible. When the process is done, the captured clips appear in Studio’s clip album.

Adjusting video-capture settings in Studio

To make sure Studio is ready to capture analog video instead of digital video, click the Settings button at the bottom of the capture window. The Pinnacle Studio Setup Options dialog box appears. Click the Capture Source tab to bring it to the front. On that tab, review the following settings:

• Video: Choose your analog capture source in this menu. The choices in the menu will vary depending upon what hardware you have installed.
• Audio: This menu should match the Video menu.
• Use Overlay and Capture Preview: I recommend that you leave both these options disabled. Leaving these options on may cause dropped frames (that is, some video frames are missed during the capture) on some computers.
• Scene detection during video capture: This setting determines when a new scene is created. For most purposes, I recommend choosing “Automatic based on video content” for analog capture.
• Data rate: This section tells you how fast your hard disk can read or write. Click the Test Data Rate button to get a current speed estimate. Ideally, both numbers should be higher than 10,000 kilobytes per second for analog capture. If your system can’t reach that speed.

If you have trouble with dropped frames when you capture analog video, try disabling automatic scene detection by choosing the No Automatic Scene Detection option. Scene detection uses some computer resources, and it can cause some dropped frames if your computer isn’t quite fast enough. When you’re done reviewing settings on the Capture Source tab, click OK to close the Setup Options dialog box. You are almost ready to begin capturing analog video. Like many analog video capture programs, Studio lets you finetune the audio and video that will be captured. Click the buttons on either side of the capture controller to open the Video Input and Audio Capture control. These control panels allow you to adjust color, brightness, and audio levels of the incoming video. On the Video Input control panel, first choose whether you’re going to capture video from the Composite or S-Video connectors using the radio buttons under Video Input. The Audio Capture control panel allows you to turn audio capture on or off.
Now press Play on your VCR or camcorder to begin playing the video you plan to capture, but don’t start capturing it yet. As you play the analog video, watch the picture in the preview screen in the upper right corner of the Studio program window. If you don’t like the picture quality, you can use the brightness, contrast, sharpness, hue, and color saturation sliders on the Video Input control panel to adjust the picture. Experiment a bit with the settings to achieve the best result.
As you play your analog tape, you’ll probably notice that although you can see the video picture in the preview window, you can’t hear the sound through your computer’s speakers. That’s okay. Keep an eye on the audio meters on the Audio Capture control panel. They should move up and down as the movie plays. Ideally, most audio will be in the high green or low yellow portion of the audio meters. Adjust the audio-level slider between the meters if the levels seem too high or too low. If the audio seems biased too much to the left or right, adjust the balance slider at the bottom of the control panel. If you’re lucky, the tape you’re going to capture from has color bars and a tone at the beginning or end. In that case, use the bars and tone to calibrate your video picture and sound. The tone is really handy because it’s a standard 1KHz (kilohertz) tone designed specifically for calibrating audio levels. Adjust the audio-level slider so both meters read just at the bottom of the yellow. When you’re done playing with the settings in the Video and Audio control panels, stop the tape in your VCR or camcorder and rewind it back to where you want to begin capturing.

Using a video converter

Video converters are kind of neat because they don’t require you to break out the tools and open up your computer case. As their name implies, video converters convert analog video of your visit in Aztec ruins to digital before it even gets inside your computer.
The converter has connectors for your analog VCR or camcorder, and it connects to your computer via the FireWire port. Converters are available at many electronics retailers for about $200. Common video converters include

• Canopus ADVC-50: www.canopuscorp.com
• Data Video DAC-100: www.datavideo-tek.com
• Dazzle Hollywood DV Bridge: www.dazzle.com

All three of these video converters are compatible with both Macintosh and Windows computers. Video converters pipe in video using a FireWire port —so as far as your computer is concerned, you’re capturing digital video. Capturing analog video using a video converter is just like capturing digital video. The only difference is that you’ll have to manually press Play on your analog camcorder or VCR before you start to capture.
If you have a digital camcorder, you might be able to use it as a video converter for analog video. Digital camcorders have analog connectors so you can hook them up to a regular VCR. Hook up a VCR to the camcorder, set up the camcorder and your computer for digital capture, and push play on the VCR. If the video picture from the VCR appears on the capture-preview screen on your computer, you can use this setup to capture analog video. This should work without having to first record the video onto tape in your digital camcorder, which means that using your camcorder as a converter won’t cause increased wear on the camcorder. Alas, some camcorders won’t allow analog input while a FireWire cable is plugged in. You’ll have to experiment with your own camera to find out if this method will work.