Three Minor Scales

Chapter I and II have been focused exclusively on the major scale. In Chapter III, we will finally explore scales other than the major scale. The first one we will treat is the variations in minor scales.

So far we have consistently referred to this scale as the “minor scale“. However, in reality, there are several derivative forms of the minor scale. We will examine them in this session.

1. Natural Minor

Firstly, the conventional minor scale we’ve been using is more accurately referred to as the Natural Minor Scale. This is because it is the scale in its natural state without any alterations.

Since this scale is already familiar, there is nothing more to say.

Insufficient Centripetal Force

However, as we have learned about the tonal gravitation theory in Chapter I, we notice one thing. In major keys, just a half step-below the tonal center, there is ti, the “leading tone“.

The strongly inclined leading tone ascends by a half step, concluding on do. There is a pronounced sense of resolution there, and utilizing it is fundamental in melody composition.

On the other hand, the world of the minor scale revolves around la instead of do.

Metaphorically speaking, to firmly build the “minor empire”, the centripetal force of la as the leader is indispensable. However, upon reexamining the arrangement of members, there is a concern — unlike the relationship between do and ti mentioned earlier, there is no strong half-step relationship in la.

Below la is the whole-tone-distant so. If left as is, we will lose the beauty of half-step resolution.

Subtonic

In Chapter I, the names of each note in the scale were introduced. In the major scale, the seventh note is called the leading tone, but in fact, in the natural minor keys, the seventh note is called the Subtonic.

---

This note, a whole tone below, doesn’t quite “lead” the melody strongly to the tonic. It’s just sitting below the tonic, Hence “subtonic”. In other words, in the minor scale, the gravitational structure around la as the center is weak. It’s like a boss who is not respected by their subordinates at all; the “loyalty” of subordinates is insufficient.

So, in the world of classical music, modifications to the minor scale were made to address this imbalance between major and minor keys.

2. Harmonic Minor

The solution is simple: raise the note so to so♯. By doing so, it is expected that the gravitational pull towards the center is greatly reinforced, similar to major keys.

Even if it means abandoning so, a former comrade, la chose to bring in a note half-step below for its vassal. In music theory, when referring to the “leading tone in minor key”, it indicates this so♯, since the term “leading tone” is defined as “the tone half-step below the tonic”.

And thus, the scale with the sharp on so is called the Harmonic Minor Scale. How much effect does a mere half-step alteration have? Seeing is believing. Let’s listen to the comparison.

Here is the natural minor. The gravitational pull towards the center still feels somewhat weak. Let’s add a sharp to so to enhance the energy.

This is the harmonic minor version! The sense of resolution is significantly heightened. In the classical era, this became the preferred foundation.

3. Melodic Minor

However, there is an issue with the harmonic minor too. As a result of sharpening so, the gap between fa and so^♯ becomes a bit too wide.

So, in the harmonic minor track you heard earlier, there is a somewhat Arabian or Persian flavor, a quite distinctive resonance. The distance from fa to so^♯ is called a “Augmented 2nd” in full interval names¹.

This interval, while being adjacent in a stepwise relationship within the scale, is actually separated by 3 semitones in terms of distance. In other words, the step difference here is exceptionally large, like a bumpy staircase. This is the weakness of the harmonic minor.

Therefore, in order to better balance the steps, people in the past devised a method to sharpen fa as well.

This scale, balanced for melodic lines, is known as the Melodic Minor Scale as it places emphasis on the beauty of melody. The large gap disappearing, the Arabian-like quality vanishes, and it evolves into a more user-friendly scale!

In this way, the minor scale, jealous of the gravitational pull towards the tonic that the major scale possesses, distorts its form. In fact, even classical theory books sometimes employ metaphors involving gravity to explain this phenomenon.

Expanding on the analogy to gravity might clarify these melodic tendencies. For a line to ascend from 5ˆ to 1ˆ, a certain force must be applied to raise ♯6ˆ and ♯7ˆ and propel the melody upward to 1ˆ. If the melody rises from 5ˆ to ♮6ˆ or ♮7ˆ, then the line lacks the momentum to attain 1ˆ and drops back down to 5ˆ.

Solomon, Jason W.. Music Theory Essentials (p.25).

By framing it with the metaphor of gravitation, the workings of scales become more understandable. This is the Tonal Gravitation Theory.

Precautions for Use

Let’s once again compare the three minor scales and the major scale.

As you can see, the notes shifted upwards for whatever reasons, the melodic minor scale structurally becomes closer to the major scale. Well, it’s a damn natural result, considering that the modification began with the thirst for the half-step relationships that the major scale possesses. But it is important to recognize that they are connected in relationships with only one note difference, from the natural minor to the major.

The fact that a melodic minor scale is structurally similar to a major scale carries a certain risk. With the difference lying only in the presence/absence of a sharp on do, depending on the phrase, it may become hard to convey the original sense of the minor key.

This is a phrase created using an A Melodic Minor without much thought, but the phrasing is definitely leaning towards A Major, and the musical concept feels ambiguous somewhere. You’re faced with the sad reality that if you twist the scale to obtain something, something else will go wrong… Especially you suffer a big loss when so♯ and fa♯ are descending.

Originally created to enhance the centrality of la, so♯ is expected to go up to emphasizes the dignity of the tonal center. However, the movements like so♯-fa♯-mi deviates from the original intent. Also fa♯, brought in to shorten the distance to so♯, would be better off eliminated if it moves in the pattern like fa♯-mi–fa♯. It seems like It’s just letting the major scale folks play freely, rather than establishing a minor key empire… On the contrary, the “effective control” of the major key people has progressed.

To resolve this, in melodic minor, it is common to switch to natural minor or harmonic minor during the descending motion. To put it another way, Melodic minor is only used for ascending lines.

Melodic minor all the way

Natural minor when descending

Harmonic minor when descending

The latter two maintain an appropriate distance from the major key, ensuring a proper identity as a minor key. The use of so♯ and fa♯ is limited to the necessary moments and in a manner favorable to the king, la. Finally, an ideal environment for la has been achieved!

In classical music theory books, it is generally recommended to use the natural minor scale during the descent. However, this can vary depending on the specific phrase structure and the harmonic context of the sounding chords.

“Greensleeves” is a typical example where you can find descending melodic minor melody. The last phrase, “lady greensleeves”, is sung with the melody “so♯-fa♯-so♯-la“.
Here, the so♯ once goes against the tendency and descends. However, it quickly turns around and ascends again, so this line doesn’t sound unnatural. If the overall melody line follows a logical shape like this, it’s possible for so♯ to descend in the melodic minor.

Therefore, the Melodic Minor scale is a somewhat unique entity. Rather than freely composing with it like with major or natural minor scales, it functions more like a “temporary staff”, called upon to work only during specific phrases.