Splitting and Joining Stereo Tracks - Audacity Development Manual

# Splitting and Joining Stereo Tracks

From Audacity Development Manual

Using the commands in the Audio Track Dropdown Menu you can:

- Split a stereo track into separate tracks for left and right channels
- Split a stereo track into two separate mono tracks
- Join two mono, left or right tracks into one stereo track.

## Splitting a Stereo Track

Here is a stereo track:

You can make separate left-channel and right-channel tracks so that you can edit them separately. Open the Audio Track Dropdown Menu and choose Split Stereo Track:

Now you can see the two tracks marked "Left" and "Right":

Note carefully that after this split the Left channel is panned hard left and the Right channel is panned hard right. You can change these pan settings as part of your editing, if required.

## Splitting a Stereo Track into two Mono Tracks

You can instead choose to split a stereo track into two mono tracks.

After choosing "Split Stereo to Mono" from the Track Dropdown Menu on the original stereo track we get two separate mono tracks:

Note that in this case both mono chanels are center-panned - different to the hard left and right panning that you get when you make a simple split of a stereo track.

## Joining tracks to make a stereo track

Choosing "Make Stereo Track" from the Track Dropdown Menu of the upper track of a pair of mono, left or right channel tracks (in any combination) will combine those two tracks into one stereo track. The upper track will become the left channel of the stereo track and the lower track will become the right channel regardless of their current designation as mono, left or right. In the example below, two mono tracks are about to be combined into one stereo track. The result of this operation will be to re-create the stereo track as shown in the first image on this page.

When joining two single-channel tracks into one stereo track be aware that:

- the gain and pan settings of the two tracks will be ignored when making the new stereo track
  - the upper track will be treated as having a pan setting of 100% left and a gain setting of 0 dB
  - the lower track will be treated as having a pan setting of 100% right and a gain setting of 0 dB
- the gain setting of the upper track will be applied to the new stereo track
- the pan setting of the resulting stereo track will be set to 0.

Thus the join action may make the balance sound different from your intentions or what you hear when playing the tracks.

- Envelopes will be retained for the left and right channels of the new stereo track, but any further envelope adjustments will be applied to both channels simultaneously which may give unexpected results.

If you want to preview the result of the Make Stereo Track command, set the gain of each track to 0 dB, set the pan of the upper track to 100% left and set the pan of the lower track to 100% right.

If you wish to retain the gain, pan and envelope settings of the two mono tracks when joining them into one stereo track, select the two tracks then choose Tracks > Mix > Mix and Render instead of joining the tracks.

## Examples using the Track Dropdown Menu

### Example 1: Applying equalization to one channel of a stereo track

Assume that you have a recording where one channel is "muffled" - lacking in high frequencies compared to the other channel.

1. Choose Split Stereo Track from the Track Dropdown Menu.
2. Select the muffled track, for example by clicking in the info area of the Track Control Panel.
3. Choose Effect > Equalization and apply the appropriate equalization curve to the track.
4. Listen to the result - if it is not as intended, choose Edit > Undo Equalization and try a different equalization curve.
5. When you are satisfied with the result, choose Make Stereo Track from the Track Dropdown Menu of the upper track.

### Example 2: Reducing the "width" of a stereo track

Assume you have a recording of a drum kit where the stereo spread of the kit sounds unnatural. The high hat sounds like it's coming from the right speaker only and the floor tom from the left speaker.

1. Choose Split Stereo to Mono from the Track Dropdown Menu, which makes two new mono tracks and sets them to mix together equally in both left and right channels of your listening equipment.
2. Adjust the pan control of the upper track to 70% left.
3. Adjust the pan control of the lower track to 70% right.
4. Listen to the result and adjust the pan controls until you get the effect you want.
5. Select the two tracks, for example by clicking info area of the Track Control Panel of one track, then holding Shift and clicking similarly in the Track Control Panel of the other track.
6. Choose Tracks > Mix > Mix and Render so that the two tracks are mixed and rendered into one stereo track. This changes the audio data and waveform to match with the audible pan settings.
   - If instead at step 6 you had chosen Make Stereo Track on the upper track, this does not render your changes: you would just get your original stereo track back again since Make Stereo Track ignores the pan settings. Use Edit > Undo Make Stereo then Tracks > Mix > Mix and Render if you choose Make Stereo Track by mistake.