Heptatonic scale

Examples include: Indian classical theory postulates seventy-two seven-tone scale types, collectively called melakarta or thaat, whereas others postulate twelve or ten (depending on the theorist) seven-tone scale types.

Several heptatonic scales in Western, Roman, Spanish, Hungarian, and Greek music can be analyzed as juxtapositions of tetrachords.

Thus starting on keynote A as above and following the notes of the ascending melodic minor (A, B, C, D, E, F♯, G♯) yields these seven modes: These modes are more awkward to use than those of the diatonic scales due to the four tones in a row yielding augmented intervals on one hand while the one tone between two semitones gives rise to diminished intervals on the other.

Verdi's Scala Enigmatica I-♭II-III-♯IV-♯V-♯VI-VII i.e. G A♭ B C♯ D♯ E♯ F♯, which is similar to the heptatonia tertia mentioned above, differing only in that the second degree here is flattened.

Melakarta is a South Indian classical method of organizing Raagas based on their unique heptatonic scales.

The postulated number of melakarta derives from arithmetical calculation and not from Carnatic practice, which uses far fewer scale forms.

Thus the number of possible forms is equal to twice the square of the number of ways a two-membered subset can be extracted from a four-membered set: Hindustani heptatonic theory additionally stipulates that the second, third, sixth and seventh degrees of heptatonic scale forms (saptak) are also allowed only two inflections each, in this case, one natural position, and one lowered (komal) position.

Chromatic circle diagrams of the four common ancohemitonic heptatonic scales.
Melodic minor scale (ascending) on A Play
Harmonic minor scale on A Play
Ionian mode C Play
Dorian mode C Play
Phrygian mode C Play
Lydian mode C Play
Mixolydian mode C. Play
Aeolian mode C Play
Locrian mode C Play
Ascending melodic minor scale on A Play
Acoustic scale on C. Play
Half diminished scale on C Play
Altered scale on C Play
Hungarian Gypsy scale
Phrygian dominant scale Play , also known as persian scale
Enigmatic scale on C Play