Introduction to Stems

Stems is a tool for processing and extracting data from songs. Users can upload songs and advanced Fadr AI will analyze and process the song in several different ways. All songs will be split into stems, have their chord progressions extracted as a midi, and have their key and tempo detected.


Splitting any song into stems is one of the most important features on Fadr. A stem is an individual track that makes up part of a song. On Fadr, songs can be split into four different stems: vocals, bass, drums, and other. The vocals stem contains all of the singing or talking from a song. The bass stem contains lower frequency instruments like a bass guitar, contrabass, or bass synth. The drums stem contains all percussive components from the song. Finally, the other stem contains everything else in the song, including standard instruments like a guitar, piano, or synth. For convenience, Fadr also provides an instrumental stem, which is just the combination of the bass, drums, and other stems. This instrumental stem is useful if you only want to remove the vocals from the song. All stems are provided as separate audio files.


Fadr AI can extract the melody from any melodic stem as a midi, regardless of the instruments present. The melody is the sequence of notes that play in that stem throughout the song. The melodies are provided in the midi file format, which can be easily dropped into any DAW to use alongside the original song or its stems. Currently, Fadr only supports midi extraction from vocals, bass, and other stems, and we are hoping to release drum midi extraction in the near future.

Fadr is also capable of extracting the chord progression from any song. A chord progression is a sequence of chords that make up the backing harmony of a song. Currently, our AI can detect major and minor chords, but does not provide extra details like whether the chord is a seventh chord or an inversion. The chord progression is provided as both a midi file and a text file. The midi file contains the chords as notes at the corresponding times in the song, and the text file provides a human-readable list of the chord progression and the start and end times of each chord, in seconds.

Key and Tempo

All uploaded songs will have their key and tempo extracted. A song’s key is the base note/chord which backs the melody and harmony of the song, and is closely related to the chord progression. A song’s tempo represents how slow or fast the song is, and is measured in beats per minute, or bpm. Fadr relies on the detected key and tempo to synchronize stems within Remix. For more information on Remix, see the Remix Documentation.

The Stems Page

The Stems Page provides the central interface for uploading and processing songs with Fadr.

Converting Songs

When the Stems page is first loaded, this screen will appear:

Blank Stems Page

To begin, drag and drop an audio file or press the “Upload Songs” button to upload an audio file.

Uploaded song

Once a song is uploaded, it can be played back and converted. We will cover using the player in the next section. Converting a song will perform all of the processing mentioned in the previous section. Press the “Convert'' button to begin converting. Multiple songs can be uploaded and converted in parallel.

Converting stens from song

Once the stems have been extracted, they will replace the original song in the player and be made available for download. At this point, the chord progression midi is still being processed.

Converting midi from song

Once all of the processing has completed, the download midi button will be available. With a Fadr subscription, your stems and midis are saved forever and can be downloaded at any time.

Song conversion complete

Saved Stems

The Saved Stems menu lists all previously converted songs.

Saved Stems menu

The search bar can be used to filter the saved stems:

Saved Stems menu with search

Each saved song has the following options and information available:

Labeled song in Saved Stems menu
  1. Upload an image. Use this to associate an image with this song.
  2. Load the saved song into the player to play back or download the stems and midi.
  3. Play/pause the preview of the original song
  4. The name of the song
  5. The detected tempo of the song
  6. The detected key of the song
  7. The date the song was converted
  8. Delete the song (permanently)

For a reminder on what a specific control does, hover the mouse over it for a short description.

Saved songs can also be loaded into the player or rearranged (temporarily) by dragging and dropping.

Saved Stem being dragged into Stems Player

The Stems Player

Whenever a song is converted or loaded from Saved Stems, it will appear in the Stems Player. The Stems Player can be used to play the song and its stems, as well as download the extracted stems and midi.

Stems Player

First, we’ll cover the top row of controls in the Stems Player:

Labeled top row of controls in Stems Player
  1. Upload an image. Use this to associate an image with this song. (This is the same as the image in the Saved Stems menu.)
  2. Seek to the beginning of the song.
  3. Play or pause the song.
  4. The name of the song.
  5. Current chord display. This shows the current chord in the chord progression from the extracted midi as the song plays back.
  6. Drag handle. Use this to drag and reorder the Stem Player if there are multiple open at the same time.
  7. Close this Stems Player.

Additionally, each stem has its own separate controls:

Labeled stem controls in Stems Player
  1. Stem waveform. This indicates the intensity of the stem’s audio over time. Click anywhere on the waveform to seek playback to that point.
  2. Progress indicator. The boundary between the yellow and white region of the waveform indicates what part of the song is currently being played back.
  3. The name of the stem.
  4. Stem type indicator. There are different icons for the four stem types: vocals, bass, drums, and other.
  5. Solo stem. This will mute all other stems.
  6. Volume. The slider can be dragged to adjust the volume. The far right setting means 100% volume, and the far left setting means 0% volume.
  7. Mute stem.
  8. Pan. The slider can be dragged to adjust the audio positioning. The far right setting means the stem plays entirely in the right ear, and the far left setting means the stem plays entirely in the left ear.

Finally, there are a few options for adjusting the view:

Labeled view options in Stems Player
  1. Zoom/scroll. Drag the edges to adjust the zoom of the waveforms. Drag the center to scroll the visible area of the waveform.
  2. Change stem count. 2 stems will display the vocals and instrumental stem. 4 stems will display the vocals, bass, drums, and other stems.

For a reminder on what a specific control does, hover the mouse over it for a short description.