Audacity Tutorial: Loading clips, Making selections and Adjusting waveforms

Become the master of your waveforms and manipulate your tracks with a superb free sound editor.

I am going to be kicking off a brand new three-part series exploring the world of sound editing. Although we could focus on software that would leave a numbness in your wallet, we will be covering a completely free and highly capable sound editor called Audacity. This application provides a simple, yet comprehensive method of creating some impressively edited content. We’re going to begin looking at how to use Audacity for some simple tasks here, before moving on to discuss more elaborate techniques in the remaining two parts.

Installing Audacity

One of the main benefits of Audacity is that it’s a cross-platform application. The program is built using the WXWindows toolkit, and has few dependencies when it comes to installation. If you are a Windows user, installation is as simple as downloading the installer and just following the instructions. Installation on Mac OS X is as quick and easy as downloading the disk image and dragging Audacity onto the desktop, while for Linux you just unpack the RPM or DEB on as normal. All of this software is available on the main Audacity website at https://www.audacityteam.org . You can turbo-charge your Audacity set-up by adding some extra tools. Some of these will be covered in part three of this series, and may be of particular interest to musicians.

One such tool is the VST (Virtual Studio Technology) Enabler, available at http://audacityteam.org. This little utility will enable the powerful VST audio plug-in system to be supported in Audacity. This is very useful for adding special effects and adjustments to your sound. Another helpful addition is the LAME encoder for creating MP3 fi les; you will need this to export from Audacity. LAME is also available from the Audacity homepage.

However, despite Audacity’s flexibility and aforementioned cross-platform nature, many of its individual plug-ins aren’t so helpful. You should be aware that many of the VST effects plug-ins are not actually cross-platform, so be sure to check their compatibility before relying on them. A number of plug-ins are available on the Audacity website. In addition, Audacity supports LADSPA (www.ladspa.org) and Nyquist (audacity.sourceforge.net/nyquist.php) plug-ins.

First impressions

Not only is Audacity a completely free piece of software, it’s cross-platform is available for Windows, Mac OS X and Linux. With the software installed, you can run it by accessing it from the Start menu in Windows, or from the application menus in Linux (or Mac OS X). When Audacity launches you’ll see that the main interface is fairly simple. In the main area of the screen we’ll be editing our files and the buttons at the top, including the transport buttons for playing, forwarding and rewinding, and a palette of editing buttons. The buttons in the top-left area of the toolbar are the main controls that we’ll be using in our editing. These include tools to cut waveforms, select regions, adjust volume, zoom into waveforms and other facilities. The tools may look simple, but looks can be deceiving. Audacity gives you a few powerful tools with the ability to create impressive results, which may seem a little strange to those used to row after row of toolbar buttons.

Loading clips

To get started, we’re going to load up a new sound file and take a look at how Audacity represents the sound clip. Audacity supports a number of different file formats, so you can choose from MP3, OGG, WAV, AU and more. The web is littered with sound clips and music that you can download legally for free, and I suggest you download some clips that are at least a minute long – this will give you enough material to play with. Once you have some clips, you can load them into Audacity from the File menu. With a clip loaded, you will see the waveform appear in the main body of the window. This waveform is the most critical part of the Audacity interface and is an accurate visual representation of your clip. We will be using this waveform in more detail later when we begin to make small cuts. To the left of the waveform you will see Mute/Solo buttons, a Panning slider and a Gain slider. A little bit of playing with these controls will show you exactly what they do and how they function. These buttons will be useful when we record with Audacity.

Making selections

The first tool we’ll look at is for Selection. This is accessible from the toolbar and is akin to the carat in a word processor. When you click on this button, we can make simple selections by dragging the mouse over the selected area. Once an area is selected, move the mouse to either side of the selection. You’ll see a hand pointer that will enable you to extend one side of the selection– this is useful for making more detailed selections. Even with these simple selections, we can still make cuts, and if you press the [Delete] key with a selection you can cut the selected audio out of the clip.

To make more detailed selections, you can use the Magnifying tool to zoom into specific parts of the waveform. The left mouse button will enable you to zoom in, and the right button will let you zoom out. With these two simple tools, we can already cut out chunks of audio that we may want removing or shortening. It’s important to note that editing in Audacity is ‘non-destructive’, so changes to the clip will only be made when the file is finally saved.

Adjusting waveforms

The next useful tool is Envelope. This button contains an icon with the image of a blue line between two small triangles. We can use this tool to make selections and adjust the shape of the waveform – this is particularly useful for increasing and reducing the volume of different areas of the waveform. To use the tool, simply click in an area inside the waveform and you’ll see a number of white dots appear in a line. These dots can be used to adjust the height of the waveform at that point. When you adjust another part of the waveform, the two points will be connected to make smooth changes in volume. Again, the closer you zoom into the wave, the more precision will be available to you for controlling your selections and adjustments.

Another benefit of using the Envelope tool is that by making lots of lines for adjustments, you can make small, subtle edits. This tool can be used for both noticeable and virtually unheard edits (an example of a useful subtle edit could for removing a sudden outburst of bad language from a recording).

Multi-track editing

One of the main benefits of Audacity is that it’s a multi-track editor. When we loaded up our first clip we edited a single file. If you load another clip with Project/Insert Audio, another waveform will appear under the existing one. If you press the Play button, both clips will play at the same time, but you can make any minor adjustments required so that the two clips sound better together. A typical use for this kind of multi-track editing is for adding some background noise or music to a section. You can also use this technique for editing out pauses and stutters, or adding voice-overs to your clips (see ‘Adding ambiance’ below for a tutorial on how to do this).

Experiment and export

Using a combination of the tools we have covered so far, you can now go and experiment with your own ideas. A good suggestion is to listen carefully to the radio and note the ways that professionals mix music and vocal content together. When you have created something that you are pleased with, you can then mix the finished work into a single file. Audacity supports exporting to MP3, WAV and OGG formats, and you can export either the full clip or a selection. These exporting tools are accessible from the File menu.

Adding ambiance

Audacity enables you to insert background effects to your vocal work with ease.
You will first need to load the main vocal sound clip into Audacity. Use the File menu to load this clip, and then edit the clip where necessary (such as adjusting volume levels, removing unwanted sound and so on). Save the project. Now, start loading in your effects clips. To do this, click on Project/Import Audio and the clip will appear below the main clip. You can use the Mute button on the main clip to hear just the effect, then edit it until you are happy with it. Use the Gain slider on the Effects Clip bar to adjust the volume. Now use the Time Shift tool to move the clip to the right position under the main clip. Use the Envelope tool to adjust volume. Finally, go to the File menu to save and export the project.

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