This weeks download is Caprice, Opus 59, part 3, no. 16, by Matteo Carcassi. This is a solo guitar piece in D harmonic minor. Again, you can tell that it is in harmonic minor because the V chord, A, in the third measure is major instead of minor. A lot of classical pieces are in harmonic, rather than natural, minor. I think that this piece points to one of the reasons why the harmonic scale is the preferred scale.
The major scale and the natural scale are essentially the same scale. Here is F major:
As you can see the C# sets D harmonic minor apart from F major. This note creates an important difference. In any key, the one, I, and the five, V, chords are the strong chords in the key. A perfect cadence, which pretty much tells the ear this is what key a piece is in, is V to I in root position. In F major the I chord is F major and the V chord is C major. So if you are in D natural minor and happen to use a C to F progression at any point, it is going to strongly imply a major key. This actually occurs in measure 6 of this piece. The song spends two measures in F, the relative major, and you know this because measure 6 starts with a C major chord and then moves to F major.
In harmonic minor, the V chord in the relative major becomes diminished. A diminished chord has a very unsettling feel, it is an unstable chord that just begs to be resolved. That resolution is frequently to the chord above it, which in this case is up to D minor. What was a strong chord in major now strongly reinforces minor. When a song is in harmonic minor it is absolutely in minor, where sometimes natural minor and major can be confused. There is just more clarity in the piece by using the harmonic minor scale. This isn't to say that a piece can't be decidedly minor in natural minor, it is just that the ways you do it are more limiting.
I am sorry if this is boring and overly technical, but you made it this far so it can't have been that bad. To those who are not reading this, you are all big jerks. I have been on a more classical bent recently. I just find the music is more deliberate and thus easier to learn from. I get more ideas for composition and technique from classical music than anything else. I promise something rocking and fun next week.