Diesis (melodic unit)
The diesis is a small melodic unit of about an augmented comma's size. The specific range varies considerably among musicians.
Just intervals
Some just intervals have been named according to this definiton of diesis.
- Porcupine comma, or maximal diesis (49.2 ¢)
- Magic comma, or small diesis (29.6 ¢)
- Tetracot comma, or minimal diesis (27.7 ¢)
- 49/48, the large septimal diesis (35.7 ¢)
- 50/49, the small septimal diesis or septimal tritonic diesis (35.0 ¢)
This is not to be confused with the related sense of the same term, for which the major diesis (648/625) was named while being way wider than the "maximal diesis".
History
The earliest usage of the term diesis was due to Philolaus in ancient Greek music to refer to an interval that is known as the limma today. Another usage, also in ancient Greek theory and notably used by Aristoxenus, would refer to a number of quartertone-sized intervals. In more recent times, Marchetto da Padova used it for fifth-tones, and finally, the modern diesis centered around 1\31 is due to Adriaan Fokker.
See also
- Diesis (disambiguation page)
- Shimmerstep