Getting Started
While major scales provide a foundational structure for much of Western music, minor scales offer a different expressive palette. Minor tonality is not defined by a single scale but by a flexible system of three related scales: natural, harmonic, and melodic. Understanding how these scales are constructed and why they differ is essential for analyzing and composing music in minor keys.
What You Should Be Able to Do
Identify the natural, harmonic, and melodic minor scales in notated music by their unique pattern of accidentals.
Aurally distinguish between the three forms of the minor scale when they are performed.
Notate the three forms of the minor scale from any given starting pitch (tonic).
Explain the specific scale-degree alterations that differentiate the harmonic and melodic minor scales from the natural minor.
Define the function of a leading tone versus a subtonic.
Key Concepts & Analysis
The three forms of the minor scale are best understood not as separate entities, but as variations on a single foundational scale. Each variation solves a particular melodic or harmonic problem. The primary lens for understanding these alterations is the function of specific scale degrees, particularly the crucial relationship between the seventh degree and the tonic.
The Natural Minor Scale: The Foundation
The natural minor scale is the baseline form, containing the exact pitches indicated by the key signature. A scale is a sequence of pitches arranged in ascending or descending order according to a specific pattern of intervals. The natural minor scale's pattern of whole (W) and half (H) steps is: W-H-W-W-H-W-W.
- Example (a natural minor): A-B-C-D-E-F-G-A
The most significant feature of the natural minor scale is its seventh degree (^7), which lies a whole step below the tonic. This scale degree is called the subtonic. Because it is a whole step away, the subtonic has a relatively weak melodic pull toward the tonic. This scale is identical to the Aeolian mode and shares a key signature with its relative major (e.g., a minor and C major).
The Harmonic Minor Scale: Creating Harmonic Drive
To create a stronger sense of resolution to the tonic, composers frequently alter the natural minor scale. The harmonic minor scale raises the seventh scale degree by a half step. This alteration transforms the subtonic into a leading tone, which is a scale degree only a half step below the tonic. This half-step relationship creates a powerful melodic and harmonic pull toward the tonic, essential for creating dominant-function harmony (like the V chord).
Pattern: W-H-W-W-H-W+H-H
Example (a harmonic minor): A-B-C-D-E-F-G#-A
This alteration introduces a unique and characteristic interval: an augmented second (an interval spanning three half steps) between the lowered sixth degree (^6) and the newly raised seventh degree (^7). While harmonically useful, this large melodic gap can sound awkward or exotic in a smooth melodic line.
The Melodic Minor Scale: Smoothing the Line
The melodic minor scale addresses the awkward augmented second of the harmonic minor scale. It does this by raising both the sixth and seventh scale degrees, but typically only in the ascending form. Raising ^6 along with ^7 removes the augmented second, creating a smoother melodic contour for ascending passages.
Ascending Pattern: W-H-W-W-W-W-H
Example (a melodic minor, ascending): A-B-C-D-E-F#-G#-A
When the melodic line descends, the strong upward pull of the leading tone is no longer needed. Therefore, the descending form of the melodic minor scale typically reverts to the pattern of the natural minor scale, lowering ^7 and ^6 back to their original state.
Descending Pattern (same as natural minor): W-W-H-W-W-H-W
Example (a melodic minor, descending): A-G-F-E-D-C-B-A
This two-part structure makes the melodic minor the most variable of the three forms.
Data & Organization Tools
This table summarizes the construction and key features of the three minor scale forms, using a minor as the reference.
| Scale Form | Ascending Scale Degrees | Descending Scale Degrees | Key Feature |
|---|---|---|---|
| Natural | 1 2 b3 4 5 b6 b7 8 | Same as ascending | Subtonic (^b7); no accidentals needed |
| Harmonic | 1 2 b3 4 5 b6 7 8 | Same as ascending | Raised ^7 (leading tone); aug 2nd |
| Melodic | 1 2 b3 4 5 6 7 8 | 8 b7 b6 5 4 b3 2 1 | Raised ^6 and ^7 (asc.); natural (desc.) |
Evidence Bank
Natural Minor: The diatonic minor scale defined by the key signature. Used for melodies that do not drive toward a strong cadence.
Harmonic Minor: Natural minor with a raised ^7. Used to create a leading tone, which enables the dominant (V) chord to resolve strongly to the tonic (i).
Melodic Minor: Natural minor with a raised ^6 and ^7 (ascending). Used to create smooth, stepwise ascending melodic lines while still providing a leading tone.
Leading Tone: The seventh scale degree when it is a half step below the tonic. Its primary function is to create tension that resolves upward to the tonic.
Subtonic: The seventh scale degree when it is a whole step below the tonic. It lacks the strong resolving tendency of a leading tone.
Augmented Second: The melodically tense interval created between ^b6 and ^7 in the harmonic minor scale.
Relative Major/Minor: A pair of major and minor keys that share the same key signature (e.g., C major and a minor).
Parallel Major/Minor: A pair of major and minor keys that share the same tonic (e.g., C major and c minor). The minor scale has a lowered ^3, ^6, and ^7 relative to the major.
Skill Snapshots
Pattern Snapshot: The three forms are defined by their treatment of ^6 and ^7.
c natural minor: C D Eb F G Ab Bb C
c harmonic minor: C D Eb F G Ab B C
c melodic minor (asc.): C D Eb F G A B C
Tendency Snapshot: The altered notes have strong melodic tendencies.
Rule: The leading tone (^7) is an active tone. Effect: It has a powerful tendency to resolve up by half step to the tonic (^1).
Rule: The raised sixth degree (^6) in an ascending melodic minor scale is also an active tone. Effect: It smooths the path to the leading tone and tends to continue upward.
Rule: The subtonic (^b7) is less active than a leading tone. Effect: It can move to the tonic (^1) or the submediant (^b6) with relative ease.
Context Snapshot: The choice of minor scale form is driven by musical context.
Baseline: A descending melody from the tonic often uses the natural minor (e.g.,
^8-^b7-^b6-^5).Contrast: A melody rising to the tonic to create a cadence will use the raised leading tone from the harmonic or melodic minor (e.g.,
^5-^#6-^#7-^8).Continuity: In practice, a single musical phrase may fluidly mix pitches from all three minor scales.
Common Misconceptions & Clarifications
Misconception: A piece is "in" harmonic minor or "in" melodic minor.
- Clarification: A piece is "in a minor key" (e.g., d minor). The composer then uses pitches from any of the three minor scale forms as needed to fulfill melodic and harmonic goals.
Misconception: The key signature for a minor key is different for each form.
- Clarification: The key signature only establishes the natural minor. The harmonic and melodic forms are created by writing in accidentals.
Misconception: The melodic minor scale must descend using the natural minor form.
- Clarification: While this is the textbook convention, composers have occasionally used the ascending form of the melodic minor in descending passages for specific coloristic effects.
Misconception: The terms "relative" and "parallel" minor are interchangeable.
- Clarification:Relative keys share a key signature (C major / a minor). Parallel keys share a tonic (C major / c minor).
Summary
The concept of a "minor key" encompasses three distinct but related scale patterns. The natural minor scale, defined by the key signature, serves as the foundation with its characteristic subtonic. To create stronger harmonic resolutions, the harmonic minor scale raises the seventh degree to form a leading tone, introducing a unique augmented second interval. The melodic minor scale smooths this interval for ascending lines by also raising the sixth degree, while typically reverting to the natural minor form for descending passages. Proficiency in identifying these scales—aurally and in notation—is crucial for understanding the melodic and harmonic language of music in minor keys.