harmonising

Harmonising is the process of adding harmony to a melody to create a complete musical texture. In practice, this involves selecting chords and, often, accompanying voices that support the melody while satisfying harmonic and voice-leading considerations. Harmonising can occur in various styles and settings, from classical four-part harmony to pop chordal accompaniment and jazz reharmonisation.

In the classical tradition, harmonising typically follows rules of tonal harmony and four-part writing. Composers compose or arrange parts for soprano, alto, tenor, and bass (SATB), ensuring smooth voice leading, consonant sonorities, controlled leaps, and appropriate cadences. Diatonic functional harmony guides chord progressions through tonic, dominant, subdominant relationships, with common cadences shaping musical phrases.

In popular and jazz practice, harmonising often emphasizes keyboard or guitar chord voicings, rhythmic chord patterns, and coloristic harmony. Jazz may employ extended and altered chords, secondary dominants, modal interchange, and reharmonisation to vary the harmonic backdrop against the melody.

Key considerations when harmonising include the key and mode, the melodic contour, the desired texture and timbre, voice-leading between parts, and avoidance of unwanted parallels. The term can also refer to the arrangement of music for choir or ensemble, where a melody is supported by harmonising parts or chords.

Harmonising has historical development, from Baroque chorale-style harmonisation to Romantic and modern approaches, reflecting evolving concepts of harmony and texture. It remains a central skill for composers, arrangers, and performers across genres.