reharmonizing

Reharmonizing is the practice of changing the harmonic support of a melody or tune while keeping the original melodic line recognizable. It is a common technique in jazz, pop, and film music, used to refresh a progression, add color, alter mood, or explore new tonal directions. By substituting different chords, borrowed chords, or altered tensions, a simple tune can acquire a markedly different emotional character without rewriting the melody.

Common methods include chord substitution, modal interchange, and chromatic approach chords. Chord substitution replaces original harmonies with alternatives such as secondary dominants, diatonic substitutions, or tritone substitutions. Modal interchange borrows chords from parallel keys or modes (for example, borrowing a major IV in a minor key). Chromatic planing and voice-leading techniques smooth or emphasize movement between adjacent chords. Altered chords, including tensions like b9, #9, or b5, can heighten dissonance and release when resolved. Arrangers may also use pedal points, nonfunctional progressions, or extended and added tones to create richer textures.

Practical considerations include maintaining the integrity of the melody, balancing interest with clarity, and adapting reharmonization to the style and skill of the performer. Effective reharmonization often relies on clear voice leading, logical resolution of tensions, and awareness of the underlying rhythm and form. In performance and composition, reharmonization can be employed to reinterpret standards, craft unique endings, or support improvisation with more harmonic scaffolding.