Volume I · Chapter 11
Melody Harmonization (The Capstone)
MUSIC 20A · C-ID MUS 120Chapter quiz →
In the musicianship bookChapter 8: Progressions, Phrases, and Cadences
Introduction: Staring at the Blank Page
This is the culmination of Volume I. You have a blank score open with a single, unaccompanied melody in the soprano, and your job is to write the alto, tenor, and bass to create a complete four-part setting.
It can be overwhelming to look at twenty melody notes and try to guess twenty chords. The secret is to work systematically, from the outside in, and to let the structure of the phrase tell you where the important decisions are.
Click any example to hear it. The examples follow one melody through all three steps.
Which Chords Can Harmonize a Note?
Every melody note belongs to three diatonic triads: the chords in which it's the root, the third, or the fifth. In a major key:
| Melody note | Chords that contain it | Function |
|---|---|---|
| 1̂ | I, IV, vi | T, PD, T |
| 2̂ | V, ii, vii° | D, PD, D |
| 3̂ | I, vi, iii | T, T, T |
| 4̂ | IV, ii, V7 (as its 7th), vii° | PD, PD, D, D |
| 5̂ | I, V, iii | T, D, T |
| 6̂ | IV, ii, vi | PD, PD, T |
| 7̂ | V, vii°, iii | D, D, T |
So you never have more than three or four choices for any note, and the phrase model (T → PD → D → T, Chapter 6) usually makes the choice for you.
Step 1: Place the Pillars (the Cadences)
Don't start at measure one and work forward. Look at the ends of phrases first. If the melody ends on 1̂ approached from 2̂ or 7̂, plan an authentic cadence (V–I). If it pauses on 2̂, 5̂, or 7̂ halfway through, plan a half cadence (on V). Write those cadence chords in first: they are your structural destinations.
Step 2: Build the Outer Frame (the Bass Line)
The soprano and bass are the most important voices: together they form the outer frame. Before thinking about the inner voices, write a strong, independent bass line under the melody:
- Use contrary motion against the soprano whenever you can.
- Use the Rule of the Octave (Chapter 9): if the melody walks by step, a bass walking the other way with inverted chords sounds natural.
- Mix root-position and first-inversion chords so the bass sings, moving mostly by step and small leaps.
- Check the outer voices for parallel and direct fifths and octaves now, before you add anything else.
Step 3: Fill In the Inner Voices
With the outer frame solid, add the alto and tenor. They have the least freedom: mostly they hold common tones or move by step to whatever chord tones are missing.
- Spacing: no more than an octave between soprano and alto, or alto and tenor.
- Doubling: double the root of root-position chords; in six-four chords double the bass; never double the leading tone.
- The final audit: go chord by chord and check every pair of voices (six pairs!) for parallel fifths and octaves, and check that every tendency tone resolves.
Common Pitfalls
| Pitfall | Fix |
|---|---|
| Choosing a new chord for every melody note at random | Plan the phrase model first; repeat a chord under two melody notes if it fits (a slower harmonic rhythm is fine). |
| Bass moves in parallel with the soprano | Look for contrary motion; use inversions to change the bass direction. |
| V → IV (a retrogression) | Keep the order T → PD → D → T. |
| The leading tone doesn't resolve, or is doubled | In V–I, put 7̂ in a voice that can rise to 1̂; never double it. |
| Hidden parallels in the inner voices | Audit all six voice pairs, not just soprano and bass. |
| Voices wander out of range | Keep each voice in the middle of its range; check the tenor especially. |
Try It: Chord Chooser
Chord Chooser
Pick a chord for each melody note. The chooser plays your harmonization with a simple keyboard voicing, colors each chord by function, and checks the phrase model and the final cadence.