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.