Audacity Tracks and Clips

From Audacity Manual

An Audacity project can contain as many tracks as you want. Each track can contain several audio clips which can be moved around independently, but share several properties of the track such as its overall volume, panning, sample rate, and sample format.

Channels, Tracks and Clips

The terms channel, track, and clip can be a little confusing, especially because some programs may use them to mean slightly different things. Within Audacity, the meaning is always consistent:

A channel is for audio input or output. Audacity can record 2 channels of input (stereo), and more if you have a special sound card or audio device that supports more than two simultaneous channels. Audacity only supports 2 channels of output, no matter what kind of audio hardware you have.
A track is like one instrument in your symphony, or one voice in your dialog. You can have as many tracks as you want, and all of them will be mixed together to create your final output, but during editing you can manipulate each track independently. If you have an interview that was recorded with two microphones, each one can go in a separate track. If you have background music, that could go in a third track. That allows you to manipulate them separately before you mix them in the end.
A clip is a piece of an audio track that you can manipulate somewhat independently from the rest of the track. For example, you can split up an interview into sentences and move the sentences around individually, even though they're all from the same track. Less commonly, you can move clips between tracks.

Tracks

All audio files that are imported, or new audio that is recorded, goes into a new track. Afterwards, you can move, copy or paste audio into existing tracks. Many track properties can be accessed by clicking the title of the track, near the upper-left corner, bringing up a menu something like this:

The options in this menu are described here Track Drop-Down Menu.

Stereo Tracks

Stereo Tracks contain a single label area to the left with two waveforms on the right. The top waveform represents the left channel and the bottom waveform represents the right channel, as in this example:

By default, the two channels of a stereo track are always edited simultaneously. However, you can split them apart and work with them independently by opening the track menu (see above) and selecting Split Stereo Track.

Splitting a track into clips

When you record some audio or import audio from a file, you get a single track. In many cases, there are natural gaps in the audio - silence between sentences or pauses between phrases in music. Those are good candidates for splitting the track into multiple clips, allowing you to manipulate the clips independently. There are five ways to get multiple clips into a track:

Split in the middle of an existing clip.
Split Cut in the middle of an existing clip.
Split Delete in the middle of an existing clip.
Paste into an empty portion of an existing track.
Drag a clip from a different track.

As an example, see what happens when you select Edit > Split, in the before and after figures below.

Time-shifting clips

To move clips around independently, use the Time Shift Tool . When you click on a clip and drag it to the left or right, this is called time-shifting, because you are changing the time that audio will be heard.

Moving a clip after splitting a track into different tracks using Split.

To move multiple clips at once, select all of the clips you want to move using the Selection Tool , then use the Time Shift Tool to click and drag. If you click inside a selection area when dragging clips with the Time Shift Tool, the selection area will move with the clip as shown above. Otherwise, the selection area will stay where it is. If you click within the selection, all selected clips will move together (see before and after figures below).

Creating a selection so you can move multiple clips at once

Note that moving clips also makes use of guides, also seen in the chapter on Audacity Selection. When you move a clip, Audacity will snap the left or right boundary of a clip to the nearest edge of a clip in any other track, making it very easy to line up clips during editing.

Moving a Clip Between Tracks

The Time Shift Tool can also be used to move a single clip between tracks.

The Audacity project in the first figure below has three tracks ("Sax 1", "Sax 2", and "Drums"). The first track has 2 clips, the second track has no clips, and the third track has 1 clip. A clip can be moved from one track to another simply by dragging it using the Time Shift Tool as shown in the second figure.

Audio clip moved from track one to track two

NOTE: if a clip contains a selection area and you click with the Time Shift Tool within the selection area Audacity will not let you drag the clip into another track. To drag a clip containing a selection area into another track, either click in the track with the Selection Tool to remove the selection, or click outside the selection area (but still inside the clip) when dragging.