Principles of voice leading

Baroque, Classical, and Romantic compositions maintain a delicate balance between the melodic (horizontal) aspect of each line and the harmonic (vertical) result of the interactions of the melodic lines. When writing music in these styles, one must strive to achieve logical tonal progressions (the vertical aspect following T-P-D patterns) while also creating independent, logical, and musical melodic lines. The guidelines set forth in Figure 25‑1 will help you meet this goal.

Connecting root-position triads

When connecting root-position chords, use contrary or oblique motion between outer voices whenever possible, which will help to prevent parallel perfect fifths and octaves. Also, prefer stepwise or same note motion in all parts whenever possible, unless stepwise motion causes undesired parallel motion between parts. Each part should be as easy to sing as possible, so if a leap must be used, small leaps are preferable to larger ones. Finally, it is preferable to double the root in any root position triad since it is generally the most important member of the chord. The exception to this procedure is with the leading tone, which should never be doubled, because it is unstable. Video T36 and Example 25-1 demonstrate these principles in a short musical passage.

Notice that in the fourth measure of “Step 3,” the alto part moved by a third instead of by stepwise motion. Had the alto part moved from G by step up to A, parallel octaves would have occurred between the bass and alto, so the alto had to move down to E instead.

Sometimes, the fifth may be omitted from a triad, in which case it is preferable to triple the root, resulting in three roots and a third. The final chord of Example 25‑2 shows a context for this doubling. Here the alto and soprano share tonic, doubling the bass, and the tenor has the third of the tonic chord. This doubling allows for the leading tone in the alto (D) to resolve up to tonic.

In Examples 25‑1 and 25‑2 above, the leading tone resolves up to tonic. In Example 25‑1, the leading tone is in the soprano voice (C in D minor). Whenever the leading tone appears in an outer voice (soprano or bass), it must resolve stepwise up to tonic. In Example 25‑2, the leading tone appears in the alto voice (D in E major). Since the leading tone appears in an inner voice (alto), another solution would be to resolve it to the fifth of the tonic chord instead of up to tonic (scale degree goes to instead of ). This procedure is called “frustrating the leading tone” and can only occur when the leading tone is in an inner voice (alto or tenor). Example 25‑3 demonstrates this procedure with the progression that appeared in Example 25‑2.

Part-writing models for root-position chords

In what follows, we will see best practices for connecting root-position chords based on the relationship of their roots.

In Example 25‑4, which shows the connection between root-position chords whose roots are related by fourth or fifth (model 1), notice the following properties:

• Keep one common tone (in this example, D in the alto voice)
• Two voices move by step (in this example, F up to G in the soprano voice, and A up to B in the tenor voice)
• Bass leaps by fourth or fifth, from chord root to chord root (in this example, D to G in the bass voice)

The second model, shown in Example 25‑5, demonstrates best practices for connecting root-position chords whose roots are a third or sixth apart. This connection has the following properties:

• Keep two common tones (in this example, C in the soprano voice and A in the tenor voice)
• One voice moves by step (in this example, E up to F in the alto voice)
• Bass moves by third or sixth (in this example, A to F in the bass voice)

The third model, shown in Example 25‑6, demonstrates best practices for connecting root-position chords whose roots are related by step. These are the most challenging connections to make without problematic parallel motion. This connection has the following properties:

• Contrary motion between the upper voices and the bass voice
• No common tone connections
• Two voices move by step in contrary motion with the bass (in this example, A steps down to G in the soprano voice, and C steps down to B in the tenor voice, while the bass moves up by step from F to G)
• One voice moves by a third in contrary motion with the bass (in this example, F moves to D in the alto voice)

Voice leading with V7 and its inversions

Preparing and resolving the dominant seventh (V7) to tonic are relatively straightforward processes, since the V7 contains several tendency tones that influence its voice leading. Here are several points to keep in mind:

• Since the seventh of the V7 is considered a dissonance, it needs special preparation. When possible, prepare the seventh by the same note; otherwise, use stepwise motion.
• Resolve the seventh of the chord (scale degree , “fa”) down by step (to scale degree , “mi” or “me”).
• Resolve the leading tone, which is the third of the chord (scale degree , “ti”) up by step (to scale degree , “do”), unless it appears in an inner voice, in which case you may “frustrate” it.
• Resolve all other voices using same-note or stepwise motion whenever possible.

These principles hold true whether the V7 appears in root position or in any inversion.

The root-position dominant seventh may be complete, meaning it has a root, third, fifth, and seventh, or it may be incomplete, meaning it has two roots, a third, and seventh (the fifth is omitted). Complete dominant seventh chords will resolve to incomplete tonic triads (those that have three roots and a third) unless the leading tone is frustrated, in which case both chords will be complete. Incomplete dominant seventh chords will resolve to complete tonic triads.

Inverted seventh chords may not be incomplete. They should always have a root, third, fifth, and seventh.

Several examples of proper resolutions of V7 appear in Example 25‑7. The unique features of each resolution are summarized beneath each example. In all of the examples, the seventh of the V7 (scale degree ) resolves down by step to scale degree , all upper voices move by step or same-note motion except when the leading tone is frustrated, and contrary and oblique motion are used between outer voices whenever possible.

Notice that the last two resolutions shown in Example 25‑7 feature unequal fifths between the alto and soprano voices (with a P5 between F and C moving to a d5 between E and B). Unlike parallel fifths (movement from P5 to P5), which should be avoided, unequal fifths are used in the styles we are modeling and will be necessary to complete some resolutions.

Part writing and voicing first-inversion triads

Most tonal compositions do not use triads in root position exclusively. Musicians use chords in inversion to create more interesting textures, stepwise bass lines, and greater variety. In general, first inversion triads are not as stable as root-position triads, but they are used in some cadences (e.g., the IAC).

Unlike with root-position chords, doubling is flexible when part writing with first-inversion chords. If given two equally plausible solutions, some people prefer to double the soprano in any first-inversion triad, but if this creates voice-leading problems, then simply double whatever note makes the voice leading smoothest without creating parallel octaves or fifths.

Ultimately, the most important principles to keep in mind while part writing with first-inversion chords are:

• Prefer stepwise or same note motion in all voices
• Prefer contrary motion between outer voices (unless there is a string of ascending first inversion chords, in which case parallel sixths or thirds are normative)
• Avoid doubling the leading tone (scale degree [latex]\hat{7}[/latex)
• Avoid parallel P5 and P8, as always

Prefer a doubling that makes it possible to execute these principles.

We will study part-writing principles for chords in second inversion in Chapter 26. For now, know that it is preferable to double the fifth, or bass, in any second-inversion triad.