Reharmonization changes the chords underneath a melody while preserving enough of the melody’s identity to recognize it. Start with the melody separated from the original accompaniment, identify its important notes, and try new chords that support or intentionally color those notes. Transposing an entire mixed loop is a different operation.
Check which parts are actually editable
With MIDI, you can keep a melodic line and rewrite the chord part. With separate audio stems, you may be able to replace the accompaniment while retaining the recorded melody. With one stereo file containing both, the original chords remain in the recording unless you can isolate them successfully.
Source separation may help in some cases, but it can leave artifacts or parts of the old harmony. Do not assume it produces clean stems. If the original harmony cannot be removed usefully, work with a melody-only source or recreate an original melodic idea you are permitted to use.
Use a held-note exercise first
Hold an E in the melody and play four different chords underneath it: Cmaj7, Am7, Fmaj7, and Dm9. E is the third of C, the fifth of A minor, the major seventh of F, and the ninth of D minor. The same melodic pitch takes a different role in each chord.
- Cmaj7: C–E–G–B.
- Am7: A–C–E–G.
- Fmaj7: F–A–C–E.
- Dm9: D–F–A–C–E.
Play one chord per bar and keep the E above the accompaniment. Compare the color and the sense of resolution. These are possible relationships, not instructions that every melody note must be a chord tone or extension.
Map the melody’s strong notes
Mark sustained notes, accented onsets, and phrase endings. These moments usually deserve the closest attention because the harmony has more time to establish a relationship with them. Brief passing notes may tolerate a different treatment from a long phrase-ending note.
For a melody G–E–D–C, one note per bar, try Cmaj7–Am7–G7–Cmaj7. Then keep the same melody and compare Em7–Fmaj7–Dm7–Cmaj7. Listen to each sustained relationship and the whole phrase. There is no single emotionally correct progression for those notes.
Change the bass before adding many new chords
Keep a C-major triad in the upper part and try C, A, and F below it in turn. The bass changes how the upper notes are heard. C/E is an inversion of C major; A under C–E–G implies an A-minor-seventh sonority; F under the same upper triad implies Fmaj9 without its third.
That last option is intentionally incomplete. Add A if you want the F-major quality stated clearly. Naming the actual notes prevents a useful voicing experiment from becoming a vague claim that any bass note works equally well.
Use voice leading to connect the changes
Keep shared notes and move other chord tones by small intervals when that fits the sound. Spread low-register notes so the bass does not become muddy. You can omit a fifth in many practical voicings, but retain enough information to communicate the intended chord quality.
In a DAW, put the melody and accompaniment on separate channels. Duplicate the original before editing, then compare alternatives with the same instrument and similar loudness. That isolates the harmonic decision from a preset change.
Know when to keep the original harmony
A new progression is not automatically an improvement. If the melody loses its sense of direction, simplify the substitutions or change only one chord. If the track is meant to stay hypnotic on a pedal or one chord, reharmonization may be unnecessary.
For combining existing recordings, see melody-loop compatibility. Render the final version with the MIDI-to-audio loop workflow.
Keep the melody recognizable, understand the notes in the new harmony, and check the result in the actual beat. A useful reharmonization changes the musical context deliberately rather than adding complexity for its own sake.