The δ (delta) scale is a non-octave repeating musical scale. It may be regarded as the beta scale's reciprocal since it is, "as far 'down' the (0 3 6 9) circle from α as β is 'up.'" As such it would split the minor second into eight equal parts of approximately 14 cents each Play . This would total approximately 85.7 steps per octave.
- Bohlen, Heinz: "13 Tonstufen in der Duodezime", Acustica, vol. 39 no. 2, S. Hirzel Verlag, Stuttgart, 1978, pp. 76 – 86. (German)
- Taruskin, Richard (1996). Stravinsky and the Russian Traditions: A Biography of the Works through Mavra, p.1394. ISBN 978-0-520-07099-8.
- "What about BP tonality?", The Bohlen-Pierce Site.