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 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 ) scale, both common in modern Western music. Ethnomusicologist Bruno Nettl noted that ditonic scales were common in many parts of the world but often limited to specific music types, such as children's songs, with the exception of some tribal societies. The Cheremis (Mari people) of Russia employ ditonic scales in children's songs, generally with the two notes a minor third apart.