
Colombian Harpsichordist
Group: Members
Joined: 17-August 05
Posts: 217
Member Number: 125
|
(The numbers involved with harmony can get very confusing. I will refer to chords by roman numerals, scale degrees by their names listed below, and intervals with normal numbers. So the mediant is the third degree of the scale, III is the chord on that root, and a 3rd is an interval - either the melodic leap of a 3rd or a note a 3rd or 10th etc... from the bass.)
HARMONIC PROGRESSION
As you already know, harmony is formed from the combination of multiple pitches sounding at the same time. The harmonic progression is what I will call the succession of various harmonies.
I understand that you are learning progressions from Piston as well. However, my approach will probably be different from Piston's in many ways. Harmony has never been a fixed phenomenon. In the earliest modal music, the harmonies used were whatever the many lines of counterpoint (simultaneous melodies) combined to form. To those early (and very skilled) composers, there was no notion of this harmony moving to that harmony, but rather multiple lines bound together by consonance.
In the later common practice era, some harmonic relations were recognized in their own right; that is, musicians realized that harmonies could take on a meaning of their own outside of any counterpoint. This paved the way for the new development of homophony. Some contrapuntal conventions, however, were kept in most music, like the avoidance of parallel fifths and octaves.
Finally, the impressionists (Debussy, etc...) realized that harmony itself could be freed from rules about parallels and counterpoint (though a contrapuntal element is to be found in all music) and used for its own special color.
For now we are concerned with the middle period described above. Note that this is not some sort of evolution from a "medieval" self-inhibition to modern freedom. Rather, each of these periods valued different qualities in music and excellent composers have put all of their energies into making the best music of all periods, from the medieval to the 20th century.
Composers of the common practice area followed no specific rules when writing chord progressions, but there were certain tendencies often followed. Below I will attempt to summarize my views about progressions.
V and I
You probably have a good knowledge about cadences. They are the driving force of tonal music. Their basic structure involves a falling fifth in the bass (or rising fourth) (at least for now, since we are only using root position chords), and a leading tone which rises by semitone to the tonic. In case you do not know yet, the scale degrees are named like this:
Tonic (in C Maj, C)
Supertonic (in CMaj, D)
Mediant (in CMaj, E)
Subdominant (in CMaj, F)
Dominant (in CMaj, G)
Submediant (in Spanish, oddly enough, they call it the Superdominant) (in CMaj, A)
Subtonic (if a whole step from the tonic) (in Cmin, Bb)
Leading tone (if a half step from the tonic) (in Cmaj or Cmin, B)
As you can see, a normal major scale always has a natural leading tone a minor second beneath the tonic. In this lesson we are still only considering the major mode.
Cadences like the V - I progression are the punctuation of music, ending each thought or phrase. For a cadence to be conclusive, leading tone must ascend to the tonic note. Open my cadence examples file.
The cadence of measure one is not very satisfying because the leading tone in the tenor does not ascend to the tonic.
The cadence of measure two is much more satisfying beacuse the leading tone ascends to the tonic. When the tonic note of I ends up in the highest voice, a cadence is at its most final sounding and is called a perfect authentic cadence (PAC). Most tonal pieces end with a PAC like the one in measure three.
Another way to keep the tonic note in the uppermost voice of the I chord is to descend from the supertonic. In this PAC, the root of the I chord is usually tripled, since the bass moves to the tonic, the leading tone should move to the tonic, and the supertonic moves to the tonic. When writing a chord with tripled root, usually the 5th is omitted and the 3rd is used instead. Cadences with supertonic-tonic in the soprano are in measures four through six. In the cadence of measure four, for example, the tenor moves down a 3rd to fill in the 3rd of the I chord with tripled root.
Just as the leading tone "wants" to ascend to the tonic, the supertonic "wants" to descend to the tonic. So, even if the leading tone is in the upper voice, a composer might move the supertonic of the V chord down to the tonic of an I chord with tripled root.
If the 3rd is omitted in an I chord, like in measure six, a very hollow sound is produced by the "empty" fifth. For now we will carefully avoid any chord missing its third.
I will post exercises involving cadences very soon. The next few lessons will explain the functions of all the chords - ii, IV, etc...
__________________
DNSIHSXPI
|