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.
If you are new to quarter tone music and would like to listen to some repertoire, here are a few suggestions for getting started:
- 24 Preludes for Quarter Tone Systems
- Waltz in C Neutral for Solo Saxophone
- String Quartet No. 2 in Quarter-Tone System, Op. 7 - Alois Hába
If you would like to learn more about 24-TET and composing with quarter tones, consider purchasing a print or eBook copy of Introduction to Quarter Tone Composition. 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.