In this article
A chord substitution replaces a harmony with another one that serves the phrase. Start with a change that keeps important melody notes, then listen to the bass and the next chord. Shared notes make useful candidates, but do not guarantee an interchangeable result.
Hear the examples.
Choose an example, then press Play. Compare the notes as well as the sound.
C–F–G–Am
Ending on Am instead of C changes the arrival while preserving shared tones with C.
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Replace C with Am under an E melody
C is C–E–G; Am is A–C–E. They share C and E, so a melody holding E can work over either. Try C–F–G–C, then replace the last C with Am. The ending feels different even though part of the upper harmony stays familiar.
Listen to the melody’s other notes too. A held G adds a seventh to Am; that can be useful, but it changes the chord colour. Name and judge the actual combined notes instead of relying only on the original symbol.
Turn a minor chord into a secondary dominant
In C major, replace Dm with D7 before G. Dm is D–F–A; D7 is D–F♯–A–C. F♯ gives a clearer leading motion toward G, and C can move down to B.
This change introduces a note outside C major. Check that the melody is not holding F natural at the same moment unless that tension is intentional. D7 here can tonicize G briefly without changing the key of the whole section.
Borrow iv from the parallel minor
Compare F–C with F–Fm–C. Fm uses A♭ instead of A, giving the upper line A–A♭–G. C remains common throughout if you choose a close voicing.
The borrowed Fm is not diatonic to C major. Its value comes from the specific voice leading and phrase context. If the melody holds A natural, you may prefer to delay the chord change or retain F major.
Keep a controlled comparison
Duplicate the original phrase and change only one chord. Keep sound, rhythm, tempo and loudness the same. Listen with the melody and bass, then ask whether the new ending or tension supports the song.
If it does not, restore the original. A substitution is an option, not a required upgrade. Strong rhythm and clear voicing can be more valuable than an additional chromatic chord.
Keep the notes in view.
| Original | Alternative | What to check |
|---|---|---|
| C | Am | Shared C and E; new bass A |
| Dm before G | D7 before G | F becomes F♯ |
| F before C | Fm before C | A becomes A♭ |
| G–C ending | G–Am ending | Arrival is redirected |
Try it in Captain Chords.
Keep an original C-major phrase in Captain Chords, then make three copies for the substitutions above. Compare one change at a time with your melodic phrase.
See the current editing workflow.
The Captain Plugins 8 update video shows the canvas and selection-based editing.
Common questions
Can any chord with shared notes replace another?
It is a candidate, not a guarantee. Function, bass, melody and placement still matter.
Do substitutions have to stay in the key?
No. Secondary dominants and borrowed chords deliberately introduce outside notes.
Is an inversion a substitution?
Usually it is described separately. An inversion keeps the chord tones and changes the bass position; a substitution changes the harmony.