Voice Leading with Triads

How to connect chords so that each voice sings a smooth, independent melody — demonstrated with chorales by J.S. Bach.

What is Voice Leading?

Voice leading (also called part writing) is the art of moving each voice in a chord progression along its own smooth, singable melody. When four voices — Soprano, Alto, Tenor, and Bass — move independently yet blend into clear harmony, you get the sound that defined Western music from the Renaissance through the Romantic era.

Listen to this Bach chorale. Notice how each of the four voices has its own melodic line, yet they fit together into chords:

Each voice moves mostly by step (small intervals), stays within a comfortable singing range, and has its own shape. That is voice leading.

The Four Types of Motion

When two voices move from one chord to the next, their relationship falls into one of four categories:

Contrary Motion

The voices move in opposite directions — one goes up while the other goes down. This is the strongest way to maintain independence between voices.

Oblique Motion

One voice stays on the same note while the other moves.

Similar Motion

Both voices move in the same direction but by different intervals.

Parallel Motion

Both voices move in the same direction by the same interval. Parallel thirds and sixths sound great; parallel fifths and octaves are what we want to avoid (more on that below).

Notice the thirds alternate between major (M3 = 4 semitones) and minor (m3 = 3 semitones) as the voices move through the scale. The interval type changes but the quality of independence stays — unlike parallel fifths, which always fuse.

The Rules (and Why They Exist)

These rules emerged over centuries as composers discovered what makes independent vocal lines sound good together. They are not arbitrary — each one prevents a specific acoustic or practical problem.

Avoid Parallel Fifths and Octaves

When two voices move in parallel perfect fifths or octaves, they fuse into one sound and lose their independence. This was the central concern of polyphonic writing from roughly the 14th century onward.

Here is what parallel fifths sound like — notice how the two voices stop sounding like separate melodies:

Compare with parallel thirds, which preserve independence:

Acceptable parallels: thirds, sixths. Avoid: fifths, octaves (and their compounds — twelfths, unisons).

Voice Ranges

Each voice should stay within its comfortable singing range, based on the ranges found in Bach's 371 chorales:

Melody Rules

• Tendency tones resolve: 7̂ (the leading tone) resolves up to 1̂; 4̂ resolves down to 3̂.
• No augmented intervals in any single voice — they are hard to sing and sound awkward.
• Change direction after large leaps: a leap of a fifth or more should be followed by stepwise motion in the opposite direction.
• Consecutive leaps outline a triad: if a voice leaps twice in a row, those notes should spell a chord (e.g. C–E–G).

Spacing Rules

• Soprano to Alto: within an octave.
• Alto to Tenor: within an octave.
• Tenor to Bass: can exceed an octave — wider spacing sounds natural in the low register, following the pattern of the overtone series.

Connecting Chords: Root Position

In root position triads, double the root. Since a triad has three pitch classes but we need four voices, we double one note — the root is almost always the right choice.

How the upper voices move depends on the interval between the two bass notes:

Bass Moves by Third or Sixth

The two chords share two common tones. Hold them in the same voices; move the remaining voice by step.

In the opening of BWV 269, the bass moves G → E (down a third). The chords are G major (G–B–D) and E minor (E–G–B) — they share G and B. Only one voice needs to move:

Beat 1 → Beat 2: bass G → E (minor third). G stays in the soprano, B stays in the tenor. Only the alto moves: D → E (step). Maximum smoothness.

Bass Moves by Fourth or Fifth

The two chords share one common tone. You have two options:

1. Option A: Hold the common tone; move the other two voices by step.
2. Option B: Move all three upper voices in the same direction to the nearest chord tones. Use this when Option A would create spacing problems.

In BWV 347, the bass moves F♯ → C♯ (down a perfect fourth) in the first measure. This is a typical V–I relationship:

Beat 1 → Beat 2: bass F♯ → C♯ (perfect fourth down). C♯ is the common tone — it stays in the tenor. The soprano moves A → A (stays), and the alto moves F♯ → E (step down).

Bass Moves by Second

The chords share no common tones. Use contrary motion — move the three upper voices in the opposite direction from the bass. This prevents parallel fifths and octaves.

In BWV 253, the bass moves by step frequently:

Beat 2 → Beat 3 in measure 1: bass G♯ → A (up a half step). Upper voices generally move in the opposite direction or hold — contrary motion keeps the parts independent.

Bass Repeats

When the bass stays on the same note, either:

• Hold all voices (rhythmic repetition for emphasis), or
• Redistribute the upper voices to different octaves of the same chord tones — same harmony, new voicing.

This often happens at phrase endings and strong beats.

First Inversion & Second Inversion

First Inversion (6/3 Chords)

In first inversion, the third of the chord is in the bass. This creates a lighter sound and enables smooth, stepwise bass lines.

Doubling: double the soprano note (most common), or the fifth. Never double the leading tone (7̂).

First inversion chords connect smoothly in sequences and passing motion. Look for them whenever the bass moves by step — Bach uses them constantly to keep the bass melodic.

Second Inversion (6/4 Chords)

Second inversion puts the fifth in the bass. This creates an unstable sound — the interval of a fourth above the bass was treated as a dissonance in common-practice harmony. Because of this instability, 6/4 chords only appear in specific contexts:

Cadential 6/4

The most common type. A I^6/4 chord resolves to V on a strong beat, intensifying the cadence. Double the bass note (the fifth of the chord). Both upper voices step down to the V chord.

Passing 6/4

The bass moves stepwise through the 6/4 chord, connecting two stable harmonies. Occurs on a weak beat.

Pedal (Neighbor) 6/4

The bass holds a pedal tone while upper voices move to neighbor notes and back (e.g., I → IV^6/4 → I). Occurs on a weak beat.

Arpeggiating 6/4

The bass arpeggiates through chord tones of the same harmony, passing through the 6/4 position. Simply a redistribution — no change of function.

Doubling Rules Summary

The universal principle: never double a tendency tone, especially 7̂ (the leading tone).

Practice

Analyze this complete chorale excerpt. For each pair of adjacent chords, identify:

1. The bass interval (second, third, fourth, fifth, sixth?)
2. The type of motion between soprano and bass (contrary, oblique, similar, parallel?)
3. Which voices hold common tones and which move?
4. Are there any parallel fifths or octaves? (There shouldn't be.)

Then try BWV 253 — it has more stepwise bass motion, which means more contrary motion in the upper voices and more first-inversion chords:

Finally, analyze BWV 347 for bass movement by fourths and fifths — the hallmark of V–I progressions: