User Manual

Synesthesia

Color is how we see the world so it should come as no surprise that color can help us understand complex information, including music. Some musicians even experience color when hearing certain notes or chords. OnSong can render chords in color to help draw attention to them. Synesthesia is what we call color-coding certain fonts based on their interval.

Enabling Synesthesia

Synesthesia is only available when formatting chords and can be accessed through a rainbow-colored swatch at the end of the color picker. Choosing this swatch will cause the chords on the page to render in different colors based on their interval relative to the root of the key.

Changing Palettes

Tap and hold on the rainbow swatch to change the palette used for coloring chords. These include:

  • Off disables color-coded chords.
  • Default uses a basic, rainbow color scheme moving from red through violet.
  • Synesthesia uses colors that individuals experiencing the phenomenon of synesthesia report when hearing specific notes.
  • Customize... lets you choose your own colors used to render chords using the palette editor.

Choosing the Tonic

Individuals experiencing synesthesia typically visualize certain colors when hearing specific notes or pitches. Because of that, the tonic is fixed by default, meaning that each color is assigned based on the root note of the chord. In this model, a C chord is always red. You can change the tonic strategy used for assigning colors to chords:

Fixed

This is the default and maintains a specific color for the root note of the chord.

Movable

This changes the palette to assign the first color to the root of the key. For example, if you are playing in the key of A, the "A" chord would typically appear in a bluish color if using the Default palette. If the tonic is set to movable, the "A" would render in red since it is the root interval of the key.

OnSong 2026 — Last Updated on August 28, 2026