Saturday, August 29, 2009

The Audacity Audio Editor: Two Things You Didn't Know

I've been using Audacity, the free (GPL 2) audio editor, on and off for years. I always liked the interface and feature set but I ended up running unstable versions a couple of times and switched to other apps rather than downgrade. Recently I upgraded to a beta of Audacity 1.3.8 for Mac and I'm loving it! In spite of being betaware this version has been rock solid so far. I sometimes get an error message when I initially open the app but I dismiss it and the app runs fine. For a beta release I find that perfectly acceptable.

Since I started using it again I have learned a few things about Audacity. In the picture above you see what I found when I kept on zooming in on a clip I was editing. The dots on the wave form represent the volume of the individual samples making up the digital recording. I checked Audacity's manual to see if these really did represent discrete samples, or if they were just arbitrary GUI elements. They represent samples. How cool is that for free software?

My other big revelation regarding Audacity has to do with it's multi-track abilities. Audacity has supported multiple (in audio "multiple" means "more than two" or "more than stereo") independent tracks as long as I have known about it but I never put it to use. By default Audacity opens a blank stereo file with right and left linked as a single track. This is also how stereo files open by default in Audacity. In this scenario the right and left chanels are edited together.

The usefullness of editing the two sides of a stereo file is obvious. It turns out Audacity makes this a two-click process. There is a menu item labeled "Split stereo track" that turns a stereo track into two panable, independently editable mono tracks.

To the left you see where I have done this with a commercial loop (from Peace Love Productions). Then I copied bits of the original look out to newly created tracks. This is something normally associated with a DAW, not an editor, but Audacity provides everything you need to work with an arbitrary number of audio tracks. The audio on the various tracks doesn't even need to be the same bit depth.

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