Voice-Leading in Root Motion by Fifth/Fourth in Root Position Motion between chords whose roots lay a fifth apart is the most important type of motion in all of tonal harmony. (Motion where the roots are a fourth apart is equivalent to motion by fifth, through inversion, but motion by fifth should be considered to be the standard form). Because it is so important, it is not practical to solve each motion from the rule about what should not be done; instead, it is useful to learn the favourite patterns of respected composers – especially J.S. Bach. When used correctly, they save a ton of time, and are almost guaranteed to form correct voice leading, while making it far less likely that you will paint yourself into a corner. There are four of these patterns.
Common-Tone Method Between any two chords a fifth apart, there will be one tone in common – it will be the fifth of one chord and the root of the other; this tone should be held obliquely. The other two tones should move by step to the nearest chord tones, in the same direction as each other; if the bass motion is by fifth, the upper voices will move in contrary motion to the bass (so, if the bass moves by fourth instead, they will all move in similar motion). This is the smoothest possible method, and always correctly resolves leading tones. Note that these chords do not have to be and (but remember that if they are, and the key is minor, the should be a major chord).
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Complete the following progressions using the Common Tone method:
Complete the entire progression by Common Tone:
Similar Motion Method The voices of the previous method always move upwards. What if you need to move downwards? In particular, if the chord progression is – , it is very common for the melody to move – . Another very common possibility is to move all three upper voices together, in similar motion, in the opposite direction from which they would move in the common tone method; one will move by step, and the other two will skip by third. It is important to note that this method cannot be used in a – progression in which the leading tone is in the soprano, as the leading tone will not resolve correctly. It also works best when the soprano and bass move in contrary motion to each other, but this is not a strict requirement.
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Complete the following progressions using the Similar Motion method. Some of these cannot be resolved correctly by this method; do not complete them, but cross them out instead.
Complete the entire progression by similar motion.
Triple-Root Method
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While the previous method has the benefit of supporting the very common – motion in the melody, it does so at the expense of not resolving the leading tone of a – progression. We often want to do both. The result is that two upper voices both move to the chord root (as well as the bass voice), leaving us with three copies of the root. It is important in this situation that the remaining voice must move to the chordal third, as a chord should never be missing its third.
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This is a much better resolution contrapuntally, but has the distinct disadvantage of producing an incomplete chord (no fifth). It works best at a cadence, where you don’t have to move back to another chord. If you do have to move back to another chord from a tripled root, you have to use the opposite procedure: take the two upper voices that share a tone and move them by step in opposite directions.
You have to be careful with this method that the spacing between any two upper voices does not exceed an octave. Complete the following progressions using the Triple-Root method:
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If we alternate between two chords a fifth apart, as in – – , the Triple-Root procedure offers us a special opportunity. To get back from a tripled-root chord, we need to apply the reverse procedure, splitting the double-root in the upper voices into opposite directs – but not necessarily the direction from which they came. If we return in the opposite direct, we return almost to the same chord from which we began, except that to of the voices have swapped notes. This is called a Voice Exchange. It creates more melodic interest in the inner voices, and also potentially causes a switch from open position to close position. Complete the following progressions by Triple-Root, creating Voice Exchanges. Mark the voice exchange and the position.
The Tertian Leap Method The final method combines elements of the three other methods. In the Tertian Leap, the common tone is retained (as in the Common Tone method); however, one of the upper voices steps in the direction used by the Similar Motion method (which allows the – motion in the – progression). This causes roots to become fifths and fifths to become roots (this idea will become much more important later, with seventh chords). The remaining voice is the chord’s third, which leaps to also become the third of the new chord – hence the name “Tertian” (i.e., “of the third”). This has the additional advantage of producing a complete chord. Voice-crossing, overlap, and spacing is potentially an issue here, which is why the leap itself is usually done in the tenor, where there is usually more space; other voices are possible, but it cannot be used in the soprano of the – progression, because
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the leading tone will not resolve correctly. This method also creates a shift from close position to open position, or vice versa. Complete the following progressions using the Tertian Leap method. One cannot be done correctly; cross it out instead.
Notice that the tenor voice resembles the bass voice in this progression. This allows the bass and tenor to move in parallel tenths (not thirds, because of voice overlap). Complete the entire progression by Tertian Leap.
Combinations and Special Techniques 1. Sequence Notice that in the previous exercise, the voice leading of each measure looks exactly the same, but shifted by one note. This is called a sequence. Sequencing is extremely important, and you will likely learn many. Simple sequences can be created by alternating between two different types of motion. A very common example is to alternate between the Common Tone method and the Similar Motion method. Complete the following sequence by alternating Common Tone and Similar Motion:
2. Third-Progressions We have already scene how alternating between chords related by fifth provides the opportunity to write a voice exchange. It also provides the opportunity to harmonize scan segments that span a third – as, for instance, the – – progression can harmonise – – or – – . (In fact, the voice exchange created by two Triple-Root progressions is nothing more than a third progression in two voices at once, in opposite directions). These third progressions are created by combining two methods that move a voice in opposite directions, such as the Common Tone method and the Similar Motion method.
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Complete the following third progressions, using the methods indicated:
Complete the entire progression by combining methods, creating a third-progression in every measure. Maintain the smoothest possible voice leading in the soprano – it can be done with only one skip, by third. Try to incorporate all methods (Voice Exchanges are also possible).
A Note About Doubled Fifths – Use with Caution! Ideally, it is usually best in four-part voice leading to double the root of a triad. Doubled thirds are almost always avoided (always when they are the leading tone in the triad, but they creep up occasionally in minor triads – especially the triad of a deceptive cadence).
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The usual alternative to doubling the root is to double the fifth. However, this “alternative” is not equally good. Doubled fifths in a root-position-only context can only occur when both the root and third of the first chord proceed to the fifth of the second chord, and the chord with the doubled fifth can only be left be moving the two fifths separately to the root and third of the next chord (otherwise, parallel fifths or octaves will result). Although this is allowed, by doing this, you will very often paint yourself into a corner, where you will have few or no options for correct voice leading in a subsequent measure. Although doubled fifths are permitted, they should not be used without a good reason (i.e., not just for the sake of variety).
