Volume II · Chapter 19
Harmonizing the Modulating Melody (Capstone)
MUSIC 20B · C-ID MUS 130Chapter quiz →
In the musicianship bookChapter 22: Modulation to the Dominant and the RelativeChapter 24: Integration
Introduction: Putting It All Together
Bach harmonized hundreds of Lutheran hymn tunes, and in almost every one of them the harmony travels: the first phrase might cadence in the dominant, a middle phrase in the relative minor, and the last phrase back home. This chapter brings together everything in Volume II (embellishing tones, applied chords, and pivot-chord modulation) in the classic capstone task: harmonizing a melody that modulates.
The method extends the one from Chapter 11. The new first step is to work out where the melody goes before you write a single chord.
Click any example to hear it. Fermatas (𝄐) mark the phrase endings.
Step 1: Find the Keys
Look at each phrase ending (in a chorale, each fermata). For each one, ask which key the cadence belongs to. The melody gives you clues:
| Clue in the melody | Likely destination (from a major key) | Likely destination (from a minor key) |
|---|---|---|
| Raised 4̂ (F♯ in C major) leading up to 5̂ | the dominant (V) | the dominant minor (v), rarely |
| Raised 5̂ (G♯ in C major) leading up to 6̂ | the relative minor (vi) | — |
| Raised 1̂ (C♯ in C major) leading up to 2̂ | the supertonic (ii) | — |
| Lowered 7̂ (B♭ in C major) | the subdominant (IV) | — |
| The leading tone disappears (G♮ instead of G♯ in A minor) | — | the relative major (III) |
| Raised 3̂ (C♯ in A minor) leading up to 4̂ | — | the subdominant (iv) |
A chromatic note alone doesn't prove a modulation; it may be part of an applied chord. What decides it is a cadence in the new key. Also check the last note of the phrase: it should be 1̂, 3̂, or 5̂ of the new key (or 2̂, 5̂, or 7̂ of a half cadence).
Step 2: Plan the Cadences
Write the cadence chords first, in their own keys. A perfect authentic cadence in the new key needs the new key's dominant, with its leading tone (usually the chromatic note in the melody), and a predominant before it. Typical formulas: ii6–V(7)–I, IV–V7–I, or ii6–I64–V–I.
Step 3: Choose the Pivot
Work backward from the new key's dominant. The chord just before it is your pivot candidate: it must be diatonic in both keys, and it works best as a predominant in the new key (Chapter 18). Label it on two lines. Everything before the pivot belongs to the old key; everything after it, to the new key.
For the return home, the same idea runs in reverse. Often the tonic of the new key simply becomes a chord of the home key (D major's I is G major's V), which makes a very smooth pivot.
Step 4: Bass Line, Chords, and Color
- Write a strong bass line against the melody, with lots of contrary motion and a mix of root-position and inverted chords (Chapter 11).
- Inside each key, harmonize as usual. Then look for places to add color: an applied chord in front of a strong arrival (V7/IV after the opening tonic, V7/V before the cadential dominant).
- Check the outer voices for parallel and direct fifths and octaves before you fill in the inner voices.
Step 5: Inner Voices, Embellishments, and Proofreading
- Fill in alto and tenor with the smoothest possible motion; resolve every leading tone (including temporary ones) and every seventh.
- Then add a few embellishing tones (Chapter 12), mostly eighth-note passing tones in the inner voices and perhaps a 4–3 suspension at a cadence.
- Proofread: spacing, doubling, cross relations, parallels, and the two-line analysis at each pivot.
Try It: Key Detective
Key Detective
Study the melody (and listen). Where does the first phrase cadence? Then find the pivot. When you've answered both, reveal a model harmonization.
Summary
- Find the keys: look for chromatic notes and the last note of each phrase; a cadence confirms a modulation.
- Plan the cadences in their own keys.
- Choose the pivot: diatonic in both keys, ideally a predominant in the new key; label it on two lines.
- Write the bass and the chords, adding applied chords for color.
- Fill in, embellish, and proofread.