Delta scale
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 (presumably 16:15) into eight equal parts of approximately 14 cents each . This would total approximately 85.7 steps per octave. The scale step may also precisely be derived from using 50:28 (25:14, 1003.8 cents, A♯, ) to approximate the interval 3:2⁄5:4, which equals 6:5 (E♭, 315.64 cents, ). Thus the step is approximately 13.946 cents, and there are 86.049 steps per octave. The Bohlen–Pierce delta scale is based on the tritave and the 7:5:3 "wide" triad and the 9:7:5 "narrow" triad (rather than the conventional 4:5:6 triad). Notes include: 1:1 25:21 9:7 75:49 5:3 9:5 15:7 7:3 25:9 3:1 (Wikipedia).
