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Harmonic minor is a functional repair. In natural minor the dominant chord is a minor triad with no leading tone, so its pull to the tonic is weak and the harmony cannot stand. The fix is simple — raise the seventh degree.
natural minor (C): C D E♭ F G A♭ B♭ harmonic minor (C): C D E♭ F G A♭ B ← one note moves
The raised seventh is the leading tone: a semitone below the tonic, which turns the dominant chord into a major triad and restores the push toward home. It is the most common accidental in minor-key writing — hear a G♯ in a piece in A minor and this is where it comes from.
The price: an augmented second
The change has a side effect: the sixth-to-seventh step, formerly a whole tone, becomes an augmented second (A♭–B, three semitones). That interval sounds close to a minor third, is hard to sing in tune, and gives a melody an exotic tinge. Hence the further repair of melodic minor — raising the sixth as well when ascending.
Structure
| Degree | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| vs. natural minor | = | = | = | = | = | = | raised |
| vs. major | = | = | lowered | = | = | lowered | = |
Diagram: one note restored, one interval broken
Listen: the augmented second
Hear the whole scale, and pay attention to the step from the sixth to the seventh. It is wider than the others, and that step is where the exotic tinge lives.
Common misconceptions
- "Harmonic minor is a separate scale." It is one adjustment of natural minor for harmonic needs, used at dominant chords and cadences rather than necessarily throughout a piece.
- "A written sharp must be an error." A raised seventh is the most routine accidental in minor-key music, and harmonic minor is where it comes from.
- "An augmented second sounds like a minor third, so it is the same thing." Similar sound, entirely different spelling and function: three semitones spanning two letter names, not three.
- "You must choose one of the three minors." Real pieces mix them — natural minor in the melody, harmonic minor at the dominant, melodic minor in ascending runs.
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Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- 和声小调 = 自然小调升第 7 级；升 7 级用于属功能，属乐理通则
- 由此产生的第 6–7 级增二度是小调写作的常见技术问题，为通行和声学表述
Used for fact-checking only; all prose is original.