Reharmonisation means keeping the same melody but changing the chords underneath it. Think of it like serving the same dish on a different plate - the food hasn't changed, but the whole experience feels different. This is one of the most powerful arranging techniques, and it's how producers create remixes, covers, and fresh versions of existing ideas.
Same melody, different feeling
A melody usually works over multiple chord choices. Each choice gives the melody a different emotional colour. The melody note becomes a different chord tone depending on what's underneath, changing how it is heard.
Melody note E over different chords
Common techniques
1. Diatonic substitution
Swap a chord for another chord in the same key that shares notes. The simplest form of reharmonisation.
C
C E G
Am
A C E
C and Am share two notes - swapping feels gentle and natural
2. Tritone substitution
Replace a dominant 7th chord with another dominant 7th whose root is a tritone (6 semitones) away. They share the same guide tones (3rd and 7th), so the resolution still works but the bass line moves by half step instead of a fifth.
G7
Standard V7
Db7
Tritone sub
C
Resolution
Db slides down by half step to C - smooth, jazzy bass movement
3. Reharmonise for a bass line
Choose chords that give you a smooth, stepwise bass line. The melody stays the same but the new bass motion adds direction and flow.
C
C
Am/B
B
Bb
Bb
F/A
A
Ab
Ab
G
G
Descending chromatic bass: C - B - Bb - A - Ab - G
4. Quality change
Change a chord's quality (major to minor or vice versa) while keeping the same root. This is dramatic and instantly recognisable.
Original
Reharmonised
Simple vs complex reharmonisation
Simple (pop)
C
Am
F
G
Em
Am
Dm
G
Swap C for Em (shared notes)
Complex (jazz)
C
Am
F
G
Cmaj7
Eb7
Abmaj7
Db7
Tritone subs and chromatic movement
In production
Verse vs chorus
Use simpler chords in the verse and richer reharmonisation in the chorus. Same melody feels bigger without changing the notes.
Remixes and covers
Reharmonisation is the backbone of creative remixes. Take a familiar vocal and put completely different chords underneath to transform the mood.
Check for clashes
When reharmonising, make sure the melody note works with the new chord. Avoid creating unintentional minor 2nd clashes between melody and chord (unless that's the sound you want).
Key takeaway
Reharmonisation changes the chords underneath a melody to give it new emotion. Diatonic substitution is gentle (swap for shared-note chords). Tritone substitution is jazzy (swap dominant chords a tritone apart). Quality changes are dramatic (major to minor). The melody stays the same - the context around it transforms the entire feeling.
This completes the Harmony Advanced topic. Next up: Song Structure - how songs are built from sections and how to arrange them effectively.
Hear advanced harmony in action
Starts generates chord progressions using voice leading, tensions, and modulation.