unmixer is a graphical utility and Python package for creating isolated tracks (drums, bass, vocals, etc.) from music files.

unmixer is a frontend for demucs, an excellent command-line utility for music source separation from the Meta Research team. The creation of isolated tracks is handled entirely by demucs; unmixer provides a graphical interface for viewing, playing, and exporting the isolated tracks in any combination.

The easiest way to install the package is to download it from PyPI using pip. Note that unmixer depends on Python 3.11 or newer; please ensure that you have a recent version of Python installed before proceeding.

Run the following command in a shell (Linux or macOS is assumed):

$ pip install --upgrade unmixer

The package does depend on a few external Python packages available on PyPI. If you wish to sandbox your installation inside a virtual environment, you may choose to use virtualenvwrapper or a similar utility to do so.

When successfully installed, a program called unmixer will be placed on your PATH. See the Usage section below for details about how to use this program.

• The utility expects ffmpeg to be installed for mixing isolated tracks. See the project's Downloads page for instructions on downloading and installing ffmpeg.

The unmixer program is a graphical utility for exploring isolated tracks extracted from a music file.

At any time, you can use the -h or --help flags to see a summary of options that the program accepts.

$ unmixer -h
usage: unmixer [-h] [--mp3] [-o OUTPUT] [-g | -p] [music_file_or_track_dir]

create and explore isolated tracks from music files

positional arguments:
  music_file_or_track_dir
                        path to the file to unmix, or path to a directory containing isolated tracks

options:
-h, --help            show this help message and exit
--mp3, --output-mp3   output isolated tracks as MP3 files instead of WAV
-o OUTPUT, --output OUTPUT, --output-dir OUTPUT
                      path to the directory for output isolated tracks (default: ~/unmixer)
-g, --guitar          show "Guitar" track instead of "Other"
-p, --piano           show "Piano" track instead of "Other"

To create isolated tracks for a specific song, pass the path to the song to unmixer. For example:

$ unmixer /path/to/Limelight.mp3

When invoked with no arguments, unmixer will open a Song Importer window containing a button labeled Explore isolated tracks... and another button labeled Choose a song... (see the screenshot below). The Song Importer window may also be opened at any time using the keyboard shortcut Ctrl+0 (Cmd+0 on macOS).

Press the Choose a song... button and select a music file that you want to create isolated tracks from. Alternatively, you may drag a music file from elsewhere on your computer and drop it on the Song Importer window. When a song has been selected, the interface will change to reflect that the song is ready to be processed (see the screenshot below).

Use the radio buttons to set the desired output format for the isolated tracks (MP3 or WAV) and the name of the "other" track (see Customizing the "Other" Track Name, below).

If you selected the wrong song by mistake, press Choose a different song... to select a different file. When you are ready to unmix the song into isolated tracks, press the Start button at the bottom right of the Song Importer window. The interface will change to reflect that the song is being processed (see the screenshot below).

Once processing has started, the Start button will change to a Cancel button; use this button to abandon processing of the song.

Please be patient during the process of creating the isolated tracks, as it will take some time to complete! It typically takes about as long as the source song itself (or a bit longer) to create the isolated tracks for a song. For example, if a song is 5 minutes long, it will likely take roughly 5 minutes to create isolated tracks for that song.

NOTE: Although unmixer does not display a progress bar in its graphical interface showing the status of processing the song, the progress will be shown in the process's standard output (assuming the standard output is not redirected to a file). Check the shell or terminal from which you launched the unmixer UI to get a better approximation of how long it will take to process the song. A visual progress bar may be added in a future version.

Although it may be possible to speed up the process by adjusting the flags passed to demucs, the current implementation tends to favor producing higher quality isolated tracks at the expense of taking a bit longer. A future version of unmixer may allow customizing the quality, bitrate, machine learning model, or other settings that can be configured by demucs; the current version does not allow any such customization aside from selecting the output format (see below).

By default, isolated tracks are created as WAV files for the highest quality. To create MP3 files instead, the --mp3/--output-mp3 flag may be passed to unmixer. Alternatively, use the Isolated Track Output Format radio buttons in the Song Importer window to select either MP3 or WAV format.

NOTE: Mixes exported using the Track Explorer (see below) will use the same format as the source isolated track files.

The following isolated tracks are created by default:

• bass.wav (or bass.mp3)
• drums.wav (or drums.mp3)
• other.wav (or other.mp3)
• vocals.wav (or vocals.mp3)

These are the sources that are supported by demucs; unfortunately, there is currently no specific source available for guitar, piano, or any others besides bass, drums, and vocals. Any part of the song's audio that is not identified as bass, drums, or vocals will be found in the other.(mp3|wav) file.

In some cases, the isolated track other.(mp3|wav) may contain primarily a single instrument, such as a guitar or piano. In these cases, it may be useful for the resulting output track to have a corresponding name such as guitar.(mp3|wav) or piano.(mp3|wav) instead of the default other.(mp3|wav).

To change the name of the "other" track to guitar.(mp3|wav), the -g/--guitar flag may be passed to unmixer. Similarly, to change the name of the "other" track to piano.(mp3|wav), the -p/--piano flag may be passed to unmixer instead. (It is an error to pass both -g and -p at the same time.) Alternatively, use the "Other" Track Name radio buttons in the Song Importer window to select Guitar, Piano, or Other.

It is not currently possible to customize the name of the "other" track to be any arbitrary name, although this feature may be added in a future version.

By default, unmixer creates isolated tracks in subdirectories of the directory ~/unmixer. Each song's isolated tracks will be placed in a new subdirectory of the output directory named based on the song's filename. For example, isolated tracks for a song named Subdivisions.mp3 would be placed in the directory ~/unmixer/Subdivisions by default (note that the subdirectory does not include the .mp3 file extension).

NOTE: Creating isolated tracks for multiple songs with the same filename will result in any previous songs' isolated tracks being overwritten! If you need to process multiple distinct songs with the same filename, be sure to rename the created directories (or rename the song files themselves) to avoid conflicts!

Use the -o/--output/--output-dir flag to customize the output directory for isolated tracks created by unmixer. A subdirectory of this directory will be created for the isolated tracks, as described above.

To explore isolated tracks located in a specific directory, pass the path to the directory to unmixer. For example:

$ unmixer ~/unmixer/YYZ

Alternatively, press the Explore isolated tracks... button in the Song Importer window (see above) and select a directory containing isolated tracks. You may also drop a directory containing isolated tracks onto the Song Importer window to open a Track Explorer window for that directory.

NOTE: If you used unmixer to create isolated tracks for a song, the Track Explorer window will open automatically when the song is finished processing. (Again...please be patient!)

The Track Explorer window displays the name of the song at the top, a set of playback controls at the bottom, and a waveform and a set of controls for each isolated track found in the input directory (see the screenshot below).

Use the ▶️ (Play) / ⏸️ (Pause) button found in the playback controls at the bottom of the Track Explorer window (or press the Space bar) to control playback of the currently selected track(s). Press the ⏮️ (Restart) button to start playback at the beginning of the song. Press the ⏪️ (Skip Back) button to skip back one second at a time; press and hold the button to repeatedly skip back until the button is released. Press the ⏩️ (Skip Forward) button to skip forward one second at a time; press and hold the button to repeatedly skip forward until the button is released. The left and right arrow keys may also be used to skip back and forward, respectively.

Use the volume slider to the right of the playback controls to adjust the playback volume of the currently selected tracks. Alternatively, the keyboard shortcuts Ctrl+Up and Ctrl+Down (Cmd+Up and Cmd+Down on macOS) may be used to raise and lower the volume, respectively. Note that the underlying isolated track files themselves are NOT modified. unmixer does not currently provide a way to adjust the relative volume levels of the various isolated tracks in the overall mix, although this feature may be added in a future version.

When the song is playing, you can drag the triangular playhead (displayed above the very topmost track, with a white line extending down over all of the waveforms) to skip to a specific part of the song. Dragging the playhead while the song is paused is not currently supported.

Each track has its own Mute button and Solo button displayed to the left of the track's waveform. Use a track's Mute button to remove that track from the mix you hear when playing the song. Inversely, use a track's Solo button to hear only that track when playing the song. As the name implies, only one track may have the Solo button active at a time. A track may not be both soloed and muted at the same time; soloing a muted track will unmute the track automatically. Playback will pause automatically if all tracks are muted at the same time.

Use the Export... button found in the playback controls at the bottom of the Track Explorer to export the currently selected (i.e., unmuted) tracks as a new file. A dialog box will open, allowing you to select a destination for the file and press Save. For example, to create an instrumental mix of a song, mute the Vocals track and export the remaining tracks as a new mix.

NOTE: Exporting is disabled when only a single track is selected, since that single track is already a self-contained file that does not need to be re-exported. Similarly, exporting is also disabled when all tracks are selected, since the resulting mix is the same as the original song file that produced the isolated tracks in the first place.

If you export custom mixes in the same directory where the isolated tracks are located, the custom mixes will also be loaded if you reopen the same directory using unmixer in the future. If you want to avoid this, save any custom mixes to a different directory, such as a remixes subdirectory of the directory where the isolated tracks are located.

In the same way as when creating isolated tracks (see above), the -g/--guitar flag may be passed to unmixer to change the displayed name of the Other track (if present) to Guitar. Similarly, to change the name of the Other track to Piano, the -p/--piano flag may be passed to unmixer instead. (It is an error to pass both -g and -p at the same time.) It is not currently possible to customize the name of the Other track to be any arbitrary name, although this feature may be added in a future version.