May 7, 2004

Learning to use Audacity

Author: Joe Barr

Audacity is a free-as-in-GPLd, cross-platform sound editor for Windows, Mac, and Unix. I've recently spent some time learning how to use it. I can tell you already that it's a gem, ranking up there in my all-time top ten list of free Linux applications. Before the review police start whacking away on this story, let me make one thing perfectly clear: This is not a review. I'll leave that to those who know a lot more about sound engineering than I do. This is the tale of an ordinary user learning how to use a kick-ass application.

Luckily for me, there is an abundance of helpful information available for Audacity. The built-in help is good, and there is a tutorial to help you get started on the web. The development team also has also set up a Wiki sitefor support. But the most complete and authoritative source is the Audacity manual, which is available as a separate download.

Overview

Audacity lets you import audio tracks in a number of different formats, or to record new tracks directly. The number of tracks is unlimited. Once you've gotten the sound into Audacity, you can use a variety of tools to copy, edit, cut, paste, or apply special effects (amplify, echo, fade in, fade out, etc). One of its handiest features is its undo capability. You can undo edits even after you've saved your work as a project.

When you've finished creating it - or anytime you want - you can export your Audacity project to WAV, MP3 (requires libmp3lame.so as mentioned above), or OGG formats.

Installation

Audacity 1.2 comes with SUSE 9.1, so installation was a breeze. In fact, it may have been included in the default installation. I don't remember for sure. But in order to be able to export Audacity projects to MP3 format, I needed to install LAME 3.96, which provides the needed libmp3lame.so library. I grabbed the source code as a tarball from SourceForge and followed the "./configure, make, make install" mantra to compiled and install.

Setting your preferences

A tabbed window display offers you choices for I/O devices, audio quality, file formats, keyboard and mouse bindings, and more. After experimenting with the size of exported projects I selected OGG (Quality 6) as my default export format. Not only is OGG a patent-free alternative to MP3, it yielded slightly smaller size files. Both MP3 and OGG are compressed formats, taking up about a third of the hard disk realestate required to save the same project saved as a WAV.

I also told Audacity where to find libmp3lame.so in the section on MP3 Export. I left everything else the way Audacity had it: a sampling rate of 44,100, spectrograms with an FFT value of 256, and a maximum frequence of 8000 Hz. For those who know about this stuff, there are dozens of tweakable settings. I don't, so I tried to leave well enough alone.

A simple project

I decided to create a simple project consisting of music and voice, perhaps with some special effects, to accompany this article. The first step was to find some free-as-in-speech music.
Google took me here, where I learned about the OpenMusic Initiative and their licensing schemes.

There were four "green" licensed songs in the Music Archive. I chose an instrumental called "Penguin Island," performed by Void Main, as the source for my project's musical clips.

Importing the PenguinPlanet OGG file was as easy as clicking on Project and Import Audio from the Audacity command menu, then selecting the file from the file dialogue. It loaded in about five seconds. When it was finished, Audacity looked like you see it below. (Click on the image to see it full size.)

With the stereo music tracks in place, I was able to use the VCR-like controls to play, pause, and backup along the timeline. I searched for something I thought would be good for the intro, then for a trailer. When I found sections I thought might work, I used the Selection tool to mark off portions to be cut from the track and used Edit->Cut to get rid of them.

Next I used the Generate->Silence to separate the intro section from the conclusion. Then I was ready to record the voice track. With microphone at the ready, I pressed the record button and began to speak into the mic. I stopped after 10 or 15 seconds because I had mangled the text I was reading. No problem. Click Edit->Undo Record and the new track (Audacity always records to a new track) just disappeared. I tried again and managed to get it right, or at least a little better, the second time.

I noticed that as I recorded, I could follow the line moving across the timeline to see exactly where I was in relation to the music tracks. So instead of having to select and move sections of the audio to fit it between the musical introduction and conclusion, I simply started to speak when the intro finished.

After some final tweaking, including a "fade in" effect for the intro, I was done. I saved the project and also exported it as an OGG Vorbis file, which you can listen to here.

Don't judge the power and capabilities of Audacity based on what I did creating this demo, or you will be judging it unfairly. Instead, grab a copy for yourself and give a whirl.

You may run into a bug when recording one track and playing another at the same time. I did, and I asked the lead developer about it. He noted that the bug is actually in ALSA's OSS emulation. You can work around the bug by grabbing the latest Audacity source and configuring it with the "--with-portaudio=v19" option.

About the author

When I asked what itch he was scratching when he created Audacity, Dominic Mazzoni, still the lead developer on the project, told me "I started working on Audacity in grad school. I was working on a research project in pitch recognition and melody matching, and I needed a tool to work with audio on Linux. I thought I would spend a few months on it; I had no idea I would still be working on it years later."

It's such a powerful tool for creating digital audio, I asked if he was ever sorry that he hadn't made it commercial and proporietary instead of free software. He replied:

No, I've never regretted it. It's precisely because Audacity is free
and open that dozens of programmers, translators, artists, and
musicians have contributed to it, and that millions of people have
downloaded it. When I was in grad school I had a stipend, and now I'm
lucky enough to have a full-time job that I love. I enjoy working on
the side, and users have been generous enough to contribute some money
to cover any expenses that the project has incurred.

There are several Audacity developers who would love to spend more
time on it, if they could get support. I'm on the lookout for
sponsors who might be interested in helping to pay for a full-time
developer, which could really accelerate Audacity development.

Category:

  • Free Software
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