Your Camcorder s Microphone


Your Camcorder's Microphone

I don't want to give the impression that a camcorder's built-in microphone is a flimsy afterthought. On the contrary, it's a sophisticated device that does the best it can, given the circumstances. Where it falls flat at times is with its placement: Because camcorders are so small, there isn't much room for a microphone (Figure 5.2), so you're bound to pick up sounds that the camera is making (such as the motor advancing the tape, or the zoom control adjusting the lens).

Figure 5.2. The camera's built-in microphone is good, but it's susceptible to picking up noise from the camera and doesn't record distant subjects too well.


Another limitation is distance. The most important factor when recording audio is the distance between the microphone and subjectthe closer the better. If you're filming a birthday party, for example, you're likely to be right in the action and will pick up audio pretty well. But what about when you're doing an interview? You want the person's comments to be picked up clearly, but you don't want the camcorder to be in her face. If you're shooting from a moderate distance away (see "Depth of Field" in Chapter 2), the microphone won't pick up the sound clearly.

Tip

  • Camera manufacturers are starting to realize that audio recording can be a compelling selling point. Sony now offers a camcorder that records in Dolby 5.1 stereo surround sound, and I expect other companies will follow suit in the future.


12-bit versus 16-bit audio

Most likely, your camcorder includes the option to record in 12-bit or 16-bit audio. When you're recording in 12-bit, the microphone is grabbing sound in stereo and saving it to two separate channels (left and right), leaving two more channels to record more audio in the camera later.

If you choose to record in 16-bit audio, the quality is a bit better than what you'd hear from a CDyou're sampling more audio data than in 12-bit mode. However, that extra data occupies the available channels, so you can't add more audio to that footage (but see the tip at the end of this chapter). More data also means that your footage will take up more disk space in iMovie than 12-bit footage.

Now, with the definitions out of the way, forget about 12-bit audio. Although 16-bit takes up more disk space, iMovie prefers it; 12-bit has been known to cause audio dropouts and other problems. Plus, iMovie ignores 12-bit's two separate stereo tracks anyway, so from the software's perspective, it's just one audio stream.

Wind Screen mode

Here's a good general tip: read your camcorder manual before you go on vacation. If I hadn't been in such a hurry to take a break, I would have discovered the Wind Screen feature of my camcorder, which does a decent job of cutting down the extra noise produced by wind blowing into the microphone. It's not a perfect solution (what is?), but it would have made some of my footage sound less like I was in the middle of a tornado.

Tip

  • The Noise Reducer audio effect in iMovie HD 6 can do a fair job of cutting down exactly this type of noise. See Chapter 13.


Ambient Sound

Your biggest concern is likely to be capturing the audio of your main subject, but don't forget about ambient noise. The sounds that surround you can be just as important as the main audio to establish mood or place. It's also good for maintaining consistent noise. For example, I took some footage on the airplane en route to my aforementioned vacation, but when I brought it into iMovie, the engine noise differed depending on when the video was shot (when we started to descend) and even what side of the plane I was filming. However, I was able to use a sample of ambient noise in the background to provide an even level of noise (and also to adjust the audio so it wasn't as dominant). Record ambient noise whenever you canyou can spend a few minutes before or after your primary shooting and get plenty of material to work with later in iMovie.

This applies to "quiet" rooms as well. Even an empty room has its own audio signatureit's never completely silent. Grab a minute or two of quiet noise, too.





iMovie HD 6 & iDVD 6 for Mac OS X (Visual QuickStart Guide Series)
iMovie HD 6 and iDVD 6 for Mac OS X
ISBN: 0321423275
EAN: 2147483647
Year: 2004
Pages: 197
Authors: Jeff Carlson

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