Exploring the Minor Scales: Harmonic, Melodic, and Natural

In the world of music composition, the minor scales hold a significant place, each with its unique characteristics and applications. Although there are only three minor scales, their usage is highly flexible, and much of it is dictated by the composer. This article delves into the differences between the harmonic, melodic, and natural minor scales, their common uses, and some of the compositional strategies employed in minor key passages.

The Three Minor Scales

There are three authentic minor scales:

Natural Minor Scale: Uses the notes of the key signature only, without any alterations. No sharps, flats, or naturals are used. Harmonic Minor Scale: Raises the seventh note to create a leading tone. Melodic Minor Scale: Incorporates additional notes and is not the same in ascending and descending directions.

The notes of a natural minor scale (C-minor) are: C, D, Eb, F, G, Ab, Bb, C.

Subtle Differences in Usage

While the three minor scales share a common origin, there are subtle differences in how they are used, particularly in their mutable notes. The mutable notes in the C-minor scale are the sixth (A/Ab) and the seventh (B/Bb).

Natural Minor Scale Usage

With a natural minor scale, melodies and harmonies typically follow the same patterns as in major keys. The mutable notes (A/Ab and B/Bb) are often used in their natural form (Ab and Bb) within the scale.

Harmonic Minor Scale Usage

The harmonic minor scale raises the seventh note, creating a leading tone. In C-minor, this would be G# instead of G natural. This change provides a strong and intense resolution to the tonic, enhancing the dramatic effect of the melody and harmony.

Melodic Minor Scale Usage

The melodic minor scale is different in both its ascending and descending forms. The ascending form raises the sixth and seventh notes (G# and A# in C-minor), while the descending form reverts to the natural minor scale (G natural and B natural).

Compositional Tendencies

The treatment of mutable notes in minor scales often follows certain compositional tendencies, driven by the historical practices and style preferences. Here are some key points to consider:

Sub-dominant and Dominant Harmonies

In passages with a sub-dominant F-minor orientation, melodies typically use the lowered forms (Ab and Bb) of the mutable notes, both in ascending and descending passages. This is because the sub-dominant harmony is generally minor in nature.

Conversely, in passages with a dominant-oriented harmony, G-major melodies usually use the raised forms (A and B) of the mutable notes. This enhances the dominant feel of the harmony and creates a more dramatic effect.

It is interesting to note that a significant amount of instrumental music, especially from the late 1600s to the early 1900s, uses the lowered sixth and raised seventh steps (Ab and B). This is often taught as the "harmonic" minor scale, but it is more accurate to refer to it as a melodic minor-like pattern in minor music.

Tonic Harmonies

In passages with a tonic C-minor orientation, melodies typically use the raised forms (A and B) of the mutable notes in ascending passages and the lowered forms (Ab and Bb) in descending passages. This practice is more strictly applied in bass lines than in melody lines.

Complex Compositional Techniques

If you're looking to create more complex structures, there are several compositional techniques that can be employed. For example:

Chordal Structures and Cadences

Chords on the dominant often take the major or dominant seventh forms (G or G7) rather than the minor form (g) at cadence points, phrase endings, or section endings. This approach can indicate that a section is ending and creates a smoother resolution.

Passages based on the cycle of fifths can include patterns like i-iv-VII-III-VI-ii0-v-i-i-iv-VII-III-VI-ii65-V7-i. For example, in C-minor, this would be c-f-Bb-Eb-Ab-d0-g-c-c-f-Bb-Eb-Ab-dm7/f-G7-c.

These structures can be extended or expanded in the middle to create longer sections with intricate harmonic movement.

Other Common Techniques

Other common techniques include the use of non-cadential harmony and cadential-sounding harmonies. For instance, using g-c for non-cadential passages but G7-c or G7-C for cadential endings can create a distinct tonal feel.

Conclusion

The minor scales, with their subtle differences, offer composers a vast array of creative possibilities. By understanding and applying these scales and their variations, you can enrich your musical compositions and create more expressive and evocative pieces.