Harmonizing a chorale step by step

The goal

Given a soprano (the melody), write the other three voices in chorale style: a bass that makes counterpoint with the melody, harmonies with a regular harmonic rhythm, cadences at the fermatas, singable inner voices. It is the foremost exercise of tonal harmony courses (Piston, Kostka-Payne, Aldwell-Schachter, ABRSM grade 7–8 and diploma exams).

Procedure in eight steps

1. Analyze the melody: key, division into phrases (fermatas), notes that suggest cadences (ending on 1 = concluding cadence; on 2 or 7 = often half cadence or leading tone; on 3 = imperfect authentic cadence or a cadence in another key).
2. Decide the cadences of each phrase before anything else: PAC at the end, half cadences and cadences in related keys inside.
3. Write the bass as a second melody: first under the cadences (5–1, 4–5, 6–5 in minor…), then backward. Prefer contrary motion against the soprano, avoid parallel and hidden fifths and octaves between the outer voices.
4. Choose the chords that the bass and soprano imply (write the Roman numerals and figures: I, ii6, V6/5…). A soprano note can be the root, third or fifth of the chord: evaluate the three options.
5. Fill in alto and tenor: held common tones, stepwise motion, correct distances (maximum an octave S–A and A–T), correct doublings (in root position the root; do not double the leading tone; in first inversion double the most stable note).
6. Check the voice leading: parallels between all six pairs, resolution of the leading tone (rises), of the seventh (descends by step), prepared dissonances.
7. Add passing tones and suspensions to create the typical flow of eighth notes: especially in the bass and inner voices, and a 4–3 or 7–6 suspension before the cadences.
8. Sing or play each voice alone: if an inner voice leaps for no reason or stays still too long, fix it.

Worked example: the melody of the "Ode to Joy" (Beethoven) in C major

First phrase (4 bars) of the soprano: E E F G | G F E D | C C D E | E. D D (fermata on D: half cadence).

Why it works:

• m. 1: the bass descends C–A–F while the soprano rises E–E–F–G: contrary motion; F–E in the bass against F–G in the soprano closes with another contrary motion on I6.
• m. 2: on the soprano's F the V6/5 (B–D–F–G) makes F the seventh of the chord, which descends correctly to E on the I chord.
• m. 3: bass A–B–C under C–D–E: parallel thirds between the outer voices, allowed.
• m. 4: the cadential six-four (C/G) with the soprano on E descending to D on the V: the "textbook" half cadence.

Second phrase: E E F G | G F E D | C C D E | D. C C. You can repeat the first three bars (varying a few chords, for example IV instead of vi) and close with ii6 – V7 – I (bass F–G–C) for the perfect cadence: soprano D on the V7, final C on the I.

Stylistic variants

• Bach style: add passing eighth notes in the bass (C–B–A instead of C–A) and in the inner voices, a 4–3 suspension on the final V.
• Gospel or pop choral style: same voice leading, but with seventh and ninth chords (Cmaj9, Am9, Fmaj7, G13sus) and close voices (second clusters between alto and tenor).
• Cinematic style: harmonize the same melody with modal borrowing (Ab, Fm) in the second phrase for a change of color.

Common mistakes

• Starting from the chords instead of the bass: the bass becomes a series of roots without profile.
• Using too many root-position triads in a row: stiff sound. Alternate inversions.
• Doubling the third of major chords in an outer position, or the leading tone.
• Inner voices that leap to "go and fetch" the missing note.

Exercise for a producer

Take the melody of one of your choruses, harmonize it in four parts with this procedure, then assign the voices to four vocal tracks (or to four voices of a string patch): you will get a choral arrangement with clean voice leading, to use in an intro or a breakdown.

Related topics

The Bach chorale, Four-part SATB writing, Voice-leading rules, Cadences, Chord inversions, Nonchord tones.