Delta scale

Minor second <phonos file="Just diatonic semitone on C.mid">Play</phonos>

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 <phonos file="Delta scale step on C.mid">Play</phonos>. This would total approximately 85.7 steps per octave.

The Bohlen–Pierce delta scale is based on the tritave and the 7:5:3 "wide" triad (<phonos file="BP chord 357 just.mid">Play</phonos>) and the 9:7:5 "narrow" triad (<phonos file="BP 579 or 1st inversion chord.mid">Play</phonos>) (rather than the conventional 4:5:6 triad). Notes include:

1:1 <phonos file="Unison on C.mid">Play</phonos>

25:21 <phonos file="BP major second on C.mid">Play</phonos>

9:7 <phonos file="Septimal major third on C.mid">Play</phonos>

75:49 <phonos file="BP fifth on C.mid">Play</phonos>

5:3 <phonos file="Just major sixth on C.mid">Play</phonos>

9:5 <phonos file="Greater just minor seventh on C.mid">Play</phonos>

15:7 <phonos file="Septimal diatonic semitone on C.mid">Play</phonos>

7:3 <phonos file="Septimal minor third on C.mid">Play</phonos>

25:9 <phonos file="Classic augmented eleventh on C.mid">Play</phonos>

3:1 <phonos file="Tritave on C.mid">Play</phonos>

See also

• Alpha scale
• Beta scale
• Gamma scale

Further reading

• Bohlen, Heinz: "13 Tonstufen in der Duodezime", Acustica, vol. 39 no. 2, S. Hirzel Verlag, Stuttgart, 1978, pp. 76 – 86. (German)