Modulation
How to change key within a piece, with a pivot chord, directly or through a common tone.
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Content under musical review. It may contain inaccuracies.
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How to change key within a piece, with a pivot chord, directly or through a common tone.
Advanced
To modulate is to change tonic within a piece. It isn't a passing chord from outside the key, but a new centre your ear accepts as "home", at least for a while. Modulation brings variety to a long song, separates sections and can give a lift of energy near the end.
We start in C major and end in G major. The Am chord belongs to both keys and acts as a bridge; D7 confirms the new centre:
Modulating from C major to G majorThe note that gives the change away is F♯, which C major doesn't have:
The smoothest route uses a pivot chord, common to both keys, heard with one meaning and reinterpreted with another:
| Chord | In C major | In G major |
|---|---|---|
| C | I | IV |
| Em | iii | vi |
| G | V | I |
| Am | vi | ii |
| D7 | not in the key | V7 |
Am arrives as vi of C and leaves as ii of G, because G's V7 follows it.
String 6, Open: E2 · 6 · Scale tone
C major (0)
C major
I C · ii Dm · iii Em · IV F · V G · vi Am · vii° Bdim
Press a key to see its diatonic chords. Neighbouring keys share almost all their notes.
Compare the keys in the harmony lab and look for shared chords:
C major G majorThen try modulating to the relative minor, using Dm as the pivot (ii in C, iv in A minor):
From C major to A minorCommon types of modulation:
On guitar, a modulation usually means moving your chord shapes or scale position. Learn to spot the chord that brings in the new leading tone: it's your cue to switch scales when improvising.
Look for new accidentals that keep recurring (not a single one), a V7 resolving to a chord other than the original I and, above all, a cadence in the new key. If there's just one chromatic chord that resolves and the music soon returns, it's a tonicization, not a modulation.
Ear & improvisationTarget tonesImprovise over a backing track aiming at a specific tone of each chord.Kostka and Payne, and Piston, describe ways to reach distant keys: enharmonic modulation with the diminished seventh chord, which can be reinterpreted as the leading-tone chord of four different keys, or with the German augmented sixth, enharmonic with a dominant seventh chord; and modulation through mixture, passing through the parallel minor (C major to C minor) to reach flat keys.
There's also the modulating sequence: the same passage repeated in successive keys, for instance rising by whole steps, until it settles on the new tonic.