A quarter tone is an interval half as wide (aurally, or logarithmically) as a semitone, which is half a whole tone.

In equal temperament the quarter tone is 50 cents or 2^1/24 or 1.029302236643. In 24 tone equal temperament, or the quarter tone scale, it is the smallest step. In just intonation it is often 36:35 or 34:33.

Many composers are known for having written music including quarter tones or the quarter tone scale, including:

• Alois Haba
• Charles Ives
• Ivan Alexandrovich Vïshnegradsky

Many musical genres and cultures use quarter tones or the quarter tone scale, including:

• Arab music, see Arab tone system

List of quarter tone pieces

External links

• Tonalsoft Encyclopaedia of Tuning