Before I begin discussing chords and voice leading, I would like to make two points about music theory in general. Many have the misconception that music theory involves sets of rules from which composers wrote or write music. This is not the case. Music theory is not sets of rules, but rather sets of observations and generalizations describing what composers have done in the common practice of their art. When a music theory teacher tells the class to avoid parallel fifths, for example, that is not due to a rule passed by a legislative body of music theorists, it is due to the fact that the great classical composers whose work has been studied in order to create music theory avoided them, so it seems we should too.
The second point I wish to make is that music theory describes what has previously been heard. It is nonsensical to study the “theory” of chords, or voice leading, or scales, or intervals, or any musical thing at all if one does not first know what the thing sounds like. Music theory should explain what you have heard. If you haven’t heard it or don’t know what it sounds like, don’t study the theory of it yet, or teach it to students who don’t know what it sounds like, spend time listening first, then study (or teach) the theory.
Now on to our topic. Chords are three or more tones heard simultaneously which compositely have a tonal function in the context of the music in which they are found. Those functions are known by names such as tonic, sub-dominant, and dominant. Although there are others, we will limit our discussion for the moment to those three. If you only hear one chord, there is no way of knowing what its function is, because function is made known by the relationships of one chord to another. If you play a C major chord, it could be the tonic in C major, the dominant in F major, or the sub-dominant in G major. It is impossible to tell until we hear other chords. Play a C major chord, then a G major chord, then a C major chord again. Once we’ve heard that progression of chords, our ear will tell us that we are in C major. Our ear tells us this because we heard C major as our baseline chord, and then the G major chord, which contains the leading tone, that is the tone a minor second below the tonic, and the dominant tone, that is the tone a perfect fifth above or a perfect fourth below the tonic note. These two functions, the leading tone and the dominant, have a pull to them toward the tonic, just as gravity has a pull toward the center of the Earth. With both the leading tone and the dominant present in a single chord, the dominant chord, the pull toward the tonic is strong indeed.
Voice leading is the following of a tone with a strong pull, with the note toward which it has a strong pull. It “pertains to the manner in which individual parts or voices move from tone to tone in successive sonorities. The term “voice- leading” originates from the German Stimmführung, and refers to the di- rection of movement for tones within a single part or voice. A number of theorists have suggested that the principal purpose of voice-leading is to create perceptually independent musical lines” (Huron, 2001). It is one thing to play a C major chord, and then a G major chord, both in root position, and quite another to move each note of the chord smoothly from one to the next, each tone in an independent line or melody which, in combination with the others, forms the chords and smooth transitions in between. These independent lines follow the pulls described earlier, so that the next chord is what one would expect. When the voice leading is interrupted in order to move to an unexpected chord, variety and possibly dissonance is created, which can be quite expressive and interesting, and which can provide variety the absence of which would allow unwanted monotony to enter.
Now let’s listen to some examples of voice leading and the chord progressions through which they navigate. Because most music theory study begins with the Chorale harmonizations by J. S. Bach, we too will begin there. Here is Bach’s setting of “Auf mine Lieben Gott.” Notice the four independent melodies playing at once, the “pull” of the f-sharps to g and of the f naturals to e. The f sharps are what we would expect in a piece in G minor, because composer’s normally sharp the seventh scale tone to create a leading tone with the necessary pull to the tonic for a clear tonality to be established. The resolution of the f natural to e in the fifth measure begins a move toward the relative major, Bb, and is delayed until the beginning of the next measure, with the descending bass line in between demarcated as a separate and intervening voice by the large ascending interval at the outset. The effect is that the f natural is sustained by being held in memory while the descending line in a different register is heard, until the resolution comes, the e being connected to the e by its close proximity and by the natural pull of the f down to the e.
Now listen to the “St. Anthony Chorale” attributed to Josef Haydn. Played by a woodwind quintet, it is easier to hear the independent voices as they move along under the principal melody. (Not all 4 parts heard in the recording are shown here.)
Notice here the use of just the three chords we discussed–tonic, (1st measure), sub-dominant, (first beat of the 2nd measure), and dominant (first beat of the 3rd measure, then resolves back to the tonic)–and the independence of the lower part while at the same time it has a smooth contour throughout. The student of music theory should not, as I have eluded, conclude that this music was written by following rules, but rather that it was written in a way that conformed to what was familiar at the time, a product of musical evolution that took many centuries to get to this point. Centuries of music with no harmony, (monophony) and then with consequential harmony born of two or more melodies sung at the same time (polyphony), the by-product of which was chords, which later became more stylized and refined as musical textures changed from predominantly polyphonic (just described) to homophonic (music with harmony but featuring one voice above the others). Toby Rush (2016) described well what music theory is when he wrote, “while a lot of people think music theory is about learning the rules for how to write music, that’s not quite right. music theorists don’t create rules for writing music; they look for patterns in music that is already written.” Because many universities have a combined department of “Music Theory and Composition” it is easy to assume there is a relationship there that doesn’t exist. They certainly are related, but the relationship is that the theory explains what is, and does not prescribe what will be.
Huron, D. (September 01, 2001). Tone and Voice: A Derivation of the Rules of Voice-Leading from Perceptual Principles. Music Perception: an Interdisciplinary Journal, 19, 1, 1-64.
Rush, T. (March 10, 2016). Music Theory for Musicians and Normal People [web page]. Retrieved August 7, 2019 from http://tobyrush.com/theorypages/pdf/complete.pdf