What Makes a Scale “Harmonic”?
Four scales carry the word “harmonic” in their name. Each has at least one interval of 3 semitones between neighboring degrees (also known as an augmented 2nd or a minor 3rd), colored yellow on the wheel. That interval doesn’t appear in any of the Greek modes.
Harmonic Minor and Harmonic Major
Both scales contain an augmented 2nd interval between ♭6 and 7 - labeled 1½ on the ribbon below.
1
2
♭3
4
5
♭6
7
8
1
2
3
4
5
♭6
7
8
Double Harmonic Major and Double Harmonic Minor (Hungarian Minor)
Both of the Double Harmonic scales carry two of these augmented 2nd intervals instead of one: the ♭6-to-7 gap, plus a second, identical interval elsewhere - between ♭2 and 3 in Double Harmonic Major, between ♭3 and ♯4 in Hungarian Minor.
1
♭2
3
4
5
♭6
7
8
1
2
♭3
♯4
5
♭6
7
8
Comparisons
For a closer look at pairs of harmonic scales, see: