How do I harmonise a given melody with appropriate chords and smooth voice leading in the composing and arranging section?
Harmonise a melody using appropriate chords, cadences and voice-leading conventions as part of composing and arranging
A focused answer to the WACE Year 12 Music composing requirement on harmonising a melody. Covers choosing chords from the melody notes, planning cadences, four-part voice-leading conventions, and avoiding parallel fifths and octaves in the written exam.
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What this dot point is asking
SCSA wants harmonisation that is correct, idiomatic and smoothly voiced. The reliable approach works backwards from the cadences and forwards by good voice leading.
Choosing chords
For each strong beat, the melody note tells you which chords fit, because that note should normally belong to the chord. A melody note of C could be harmonised by C major (root), F major (fifth) or A minor (third). Choose among the options to make a good progression, favouring strong root movement (down a fifth, as in V to I and ii to V) and clear functional motion from tonic to subdominant to dominant and home.
Plan the cadences first
Cadences give a phrase its punctuation, so decide them before filling the middle:
- End a final phrase with a perfect cadence (V to I).
- End an opening or middle phrase with an imperfect cadence (ending on V) to sound unfinished.
- Use plagal or interrupted cadences for variety where the melody allows.
With the cadences fixed, harmonise the rest of the phrase to lead naturally into them.
Voice-leading conventions
In four-part (SATB) writing the way voices move between chords matters as much as the chords themselves:
- Keep any common note in the same voice.
- Move the other voices by the smallest possible interval, usually by step.
- Keep voices within their ranges and avoid voice crossing.
- Resolve the leading note up to the tonic, especially at a perfect cadence.
- Avoid consecutive (parallel) fifths and octaves between any pair of voices, the classic voice-leading error.
These conventions produce a smooth, singable inner texture rather than a series of disconnected block chords.
Adapting to style
Strict four-part rules suit a chorale or Western Art Music task. For jazz or contemporary harmonisation, the principles loosen: extended chords (sevenths and ninths), parallel motion and chord symbols over a groove are idiomatic. Match the harmonisation conventions to the style the task asks for.
Why this matters for the exam
Harmonisation tests whether you understand how harmony supports melody and how voices connect. A student who plans cadences and leads voices smoothly produces clean, convincing harmony; one who picks chords at random and leaps voices around creates parallels and awkward gaps that cost marks. This skill also strengthens the harmonic dictation and analysis questions.
Exam-style practice questions
Practice questions written in the style of SCSA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
WACE 20228 marksHarmonise the given eight-bar melody in D major in four parts (SATB). Plan a perfect cadence at the final phrase end and an imperfect cadence at the mid-point, label your chords with Roman numerals, and observe voice-leading conventions.Show worked answer →
Work from the cadences outward, then voice the chords smoothly.
Cadences first: fix a perfect cadence (V to I, A major to D major) at the end and an imperfect cadence (ending on V, A major) at the mid-point. These load-bearing chords anchor the harmonisation.
Choose chords: on each strong beat pick a chord that contains the melody note, favouring strong root movement (down a fifth) and clear tonic-subdominant-dominant motion. Label each with Roman numerals (I, IV, V, ii, vi).
Voice leading: keep common tones in the same voice, move others by step, resolve the leading note (C sharp) up to D at the perfect cadence, and check every adjacent pair of voices for consecutive fifths and octaves. Markers most heavily penalise parallel fifths and octaves and an unresolved leading note, so check these explicitly.
WACE 20215 marksDemonstrate smooth voice leading from V to I in C major in four parts, and explain each voice's movement. Identify the most commonly penalised voice-leading error and how you avoid it.Show worked answer →
In C major, V is G B D and I is C E G. Connect them by keeping the common tone and moving the rest by step.
Voice movement: keep G common to both chords in the same voice; the leading note B rises by step to C; D falls by step to C (or to E); the bass moves G to C. No voice leaps unnecessarily and the leading note resolves up, giving a clean perfect cadence.
Most penalised error: consecutive (parallel) fifths and octaves between any pair of voices. Avoid them by checking each adjacent pair of voices between the two chords; if two voices a fifth or octave apart move in the same direction to another fifth or octave, rewrite one of them by contrary or oblique motion. Markers reward the named error and a concrete avoidance method.