Audio: It's a Noisy World (page 2)

If everything else has failed, maybe a little digital noise reduction will work. Adobe Audition offers a nice noise-reduction option. There are also many other plug-ins like Sound Soap that work in a similar manner. Every program works differently, but the basics are the same. Start by identifying a section of the audio that contains only the noise. A full second would be nice, but you can work with less. Highlight the noise, and open the noise-reduction section. Audition has a button marked "Get noise from selection." You simply click it and wait for the computer to analyze the noise. When it's finished, you'll see a graph of the noise. At this point, you have the option to choose how aggressive the noise reduction should work.

There are other settings that allow you to fine-tune the process, and it will always be a trial-and-error process. You'll have to experiment to find the best ones for each type of noise. Finally, apply the noise reduction to the entire track, and listen to the results. If you used the aggressive settings, you'll probably hear some serious artifacts in the sound. These show up as gurgling noises and strange, alien sounds that weren't in your original track. You may also notice the strange addition of reverb to the ends of sounds. If you hear any of these artifacts, undo the noise reduction, and try different settings until you get something you can live with. You can also experiment with running the noise reduction two or more times with less-aggressive settings. The first pass may get rid of one type of noise but reveal another in the background. It takes some time to get it right, and the process isn't perfect, but it's better than leaving the noise in the track.

It really is a noisy world, but, using these techniques, you can gain control. The wonderful thing about reducing noise today is the Undo button. If your first try doesn't work, all you have to do is undo it and try other options. You will find a combination of recording technique, filtering and digital noise reduction that can zap even the most offensive noises.

Contributing Editor Hal Robertson is a digital media producer and technology consultant.

Sometimes, it's not possible or practical to eliminate all the noise in an audio track. In those cases, you either live with the noise or hide it using masking techniques. To mask with environmental noises, simply record a background noise track and fly it in at a reduced volume. Add some random environmental sound effects to spice it up and fully embrace the noise. Another common technique is masking with music. A simple bed of music under a dialog track can hide many undesirable noises.

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