In Western music, 12-Tone Equal Temperament, or 12-TET, is the standard for defining where all of the notes lie. The octave is divided into 12 notes, where each note is 100 cents away from the previous and next notes. Quarter tones belong to the 24-TET system, or 24-Tone Equal Temperament. The octave is divided into 24 notes, where each note is 50 cents away from the previous and next notes. These are the quarter tones that appear between the chromatic tones that exist in 12-TET.
The quarter tones are notated using sesquiflat, semiflat, semisharp, and sesquisharp notation, as shown above. This style of notation was created by Myles Skinner in his quarter tone doctoral dissertation, where he analyzed works by Easley Blackwood, Alois Hába, Charles Ives, and Ivan Wyschnegradsky. Skinner’s style of notation is beginning to emerge as the standard for quarter tone notation.
Quarter Tone Scale
The quarter tone scale is analagous to the chromatic scale of 12-TET; it is composed of the smallest interval in 24-TET, which is the quarter tone. Note that the chromatic scale can still be played in 24-TET. The audio below is a full octave of the quarter tone scale:
Chord Progression Example
The audio below represents a sample chord progression, where most chords have one or more quarter tone intervals.
If you are new to quarter tone music and would like to listen to some repertoire, here are a few suggestions for getting started:
Dig deeper into the world of 24-TET with the resources below!
The purpose of this book is to introduce composers to the world of 24-TET. Quarter tonality presents new melodic and harmonic possibilities that can bring about previously unexplored textures, colors, and atmospheres to music.
The goal of this technique book is to encourage saxophonists to learn this technique and to encourage composers to write for it. Quarter tonality presents new melodic and harmonic possibilities that can bring previously unexplored textures, colors, and atmospheres to music.