Heptatonic scale are considered subsets of a twelve-pitch scale roughly analogous to the Western chromatic scale. The first and fifth melakarta tones, corresponding to the first and eighth chromatic tones, are invariable in inflection, and the fourth melakarta tone, corresponding to the sixth or seventh chromatic tone, is allowed one of two inflections only, a natural ("shuddah") position and a raised ("tivra") position. The second and third melakarta tones can be picked from the 4 chromatic tones (second through fifth), and similarly for the sixth and seventh. Thus the number of possible forms is equal to twice the square of the number
Ditonic scale Shawnee. The ditonic scale type is recognised in Indian music, and termed the "Dvisvara" ("two tone"), but ditonic scales are not recognised as raga scales. The ditonic is among the scale types employed in traditional Nigerian music. In a study carried out in 1969, Mervyn McLean noted that among the Maori tribes he surveyed, ditonic scales comprised 17% of the scales used. Ditonic scale A ditonic scale is a musical scale or mode with two notes per octave. This is in contrast to a heptatonic (seven-note) scale such as the major scale and minor scale, or a dodecatonic (chromatic 12-note