Pity the poor natural minor scale. It had not only survived through the centuries, but flourished as pretty much the medium of choice for musical expression for quite a long time. However, its days were numbered from the moment that the major dominant chord to tonic chord progression captured the esthetic sensibilities of several generations of composers towards the end of the Medieval musical style period.
The natural minor scale started out life simply enough, and developed a harmonic language all its own. But it lacked one thing that seemed to have become an obsession with late Medieval composers: the leading tone. Let's look at the natural minor scale here (we'll use a minor for this lesson) just for reference:
Let's say we wanted to put together a piece using the minor scale and its diatonic harmonies. Look at what kind of triad we get when we build on the dominant (scale degree 5) using just the diatonic notes of the natural minor scale:
Let's see... from e to g is a minor third, so that means this is a minor triad. It just doesn't really sound like it's planning on going straight to an a minor chord, does it?
What's missing here? There's no leading tone. When we studied the scale degrees, one of the names applied to the seventh degree is "leading tone." Why the strange name? As it turns out, the leading tone is a fairly recent arrival on the scene of notes. In earlier music, the seventh scale degree was usually a whole step away from the tonic, just as it is in the natural minor scale. But when there's only a half-step between the seventh scale degree and the tonic, that seven has a definite tendency, and its tendency is to go up a half-step to the tonic. It leads you almost inescapably to the tonic. Hence, it is only when the seventh scale degree lies a half-step below the tonic that we call it the leading tone. (Otherwise, it is called the subtonic.)
Great, so now that we've gone to great lengths to define the leading tone, what's the big deal with leading tones and minor scales? Well, let's take that brief little example we just used and flesh it out a little more:
It sounds sort of OK, but the end doesn't sound very convincing. Now let's try the same example and use a leading tone in the penultimate triad:
That triad built on the dominant just before the tonic triad sounded much better here, don't you think? Well, apparently, so did a whole lot of composers several centuries ago. It sounded good to them because there had been a revolution of sorts decades earlier when they finally got a decent sounding leading tone out of their tunings for instruments, and the theretofore neglected major scale started sounding a whole lot better. One of the major scale's strengths was the fact that it contained a leading tone, and triads built on the dominant had a double incentive to go to the tonic: the circle of fifths progression between the dominant and the tonic roots, and the leading tone's drive upwards by a half-step to the tonic. A major triad built on a root of the dominant was thus far more powerful a cadential device than the "old-fashioned" minor triad that only had root motion in its arsenal of tricks to resolve to the tonic.
But the minor scale and its harmonies were still very popular, and composers still loved the flavors that using minor scale-based harmonies brought to a piece. But this major dominant triad was a force not to be taken lightly, and so a compromise (or two) was struck.
"We really like the minor scale, and we really like the leading tone," they said.
"Let's just raise the seventh scale degree of the minor scale so that we have a leading tone." And thus was born what we now call the harmonic minor
scale. When you compare the natural and harmonic minor scales:
it's pretty plain to see that the only difference between them is the harmonic minor's use of the leading tone. The harmonic minor scale, when used as a basis for harmony (hence its name!), provides the raw materials for the minor-keyed music we've come to know and love over the centuries.
Naturally, though, some people had a distinct problem with the harmonic minor scale: it is difficult to sing because of the augmented second between scale degrees 6 and 7. This difficulty, in fact, was so great that it led to the invention of another minor scale: the melodic minor
. In the melodic minor, the augmented second between 6 and 7 was mitigated by raising scale degree 6 by a half-step. Well, what seemed a good idea on paper was marred by the fact that this melodic minor scale sounded just like a major scale with the exception of the lowered scale degree 3! Something had to be done about that, so someone struck upon the idea of using a different configuration for the melodic minor that depended on which direction
the scale was being played or sung.
So, what was chosen was an ascending
melodic minor scale that used the raised scale degrees 6 and 7, and a descending
melodic minor scale that was the same as the natural minor scale. Here's the whole melodic minor scale (again in a minor) showing both the ascending and descending forms:
Why wouldn't one just use the ascending part backwards for the descending part? First of all, it is, as noted earlier, far too similar to the major scale, and this weakness would be even more apparent if the lowered scale degree 6 (as in the natural and harmonic minors) were to be eliminated altogether. Secondly, generally speaking, when a melody is descending from the tonic, it is far less likely that the harmony supporting the melody immediately following the tonic will require a leading tone; in other words, there's usually no need to jump straight to a major dominant right after the tonic.
One aspect of the melodic minor scales that frequently escapes students is that the notes of the melodic minors make rather poor choices as the basis for harmonization. Notable among the problems are some rather odd functions of the triads that are built on the ascending melodic minor (e.g., a triad built on scale degree 6 would be a diminished triad), and the same problem with lack of leading tone in the descending melodic minor that is also suffered by the natural minor. For these reasons, the melodic minor scales are seldom chosen as the source of pitches for harmonic progression. However, they are still very commonly used in melodic passagework where the underlying harmony is used in a supporting (as opposed to a more contrapuntal) role.
OK, let's do a couple of exercises.
#1. Using a key signature on a treble
clef staff, provide the following harmonic minor scales: f# minor, g minor, bb
minor, e minor
#2. Using a key signature on a bass
clef staff, provide the following ascending
melodic minor scales: d minor, b minor
#3. Using a key signature on a treble
clef staff, provide the complete ascending and descending melodic minor scales: c minor, g# minor.Answers will appear here when I'm darn good and ready!
So, now without further ado, your gardening tip: If you live in a climate that has very cold winters, one's plant choices are often somewhat limited by what kinds of perennials, trees and shrubs that can survive the deep-freeze. However, it is often quite possible to grow things that wouldn't normally survive in your climate. The key is finding planting locations that are sheltered from the full brunt of winter's fury. A spot that is buffered from winter's drying, freezing winds will lessen the cold's impact. Likewise, a location that receives ample sunlight, especially when backed by something that will reflect the solar warmth (particularly walls), can also help create a microclimate
that can allow less hardy plants to survive winter's blast. Look for spots in your garden that might have a gentler winter microclimate, and try a thing or two that you might not otherwise consider.
Next topic: TRIADS -- Third Time's a Charm! (I)