themusictheorycourse.comFree online lesson, with sound and self-correcting exercises

III.15Part III, Tonality

Modulation

By the end of this lesson, you'll recognize a modulation and the note that brings it about, and you'll know how it is written.

7 min6 questionsDanhauser § 162 to 167

Modulation is a change of key, and also the transition by which that change takes place. Danhauser only outlines this chapter, because the details belong to the study of harmony.

What brings about a modulation

A modulation is brought about by altering one or more notes of the current key. These alterations are foreign to the key you are leaving, and they belong to the key you are heading for. Most often, the note that triggers the modulation is the leading tone, or leading note in British English, or else the subdominant of the new key. Listen to two examples.

Here the music modulates from F major to C major through B♮, the leading tone of C.

Here it modulates from D major to G major through C♮, the subdominant of G.

How it is written

If the new key is only passing, you write its accidentals directly in front of the notes they affect.
If the new key is to last a while, you replace the key signature with that of the new key, after a double bar line.

When the key signature changes, you must cancel with naturals any sharps or flats that belonged to the old key signature but are not part of the new one.

Here the key signature changes from D major to F major. Naturals on F and C cancel the old signature, and then the B♭ takes over.

WorkshopInteractive Circle of FifthsFull screen

The most natural modulations go to closely related keys: adjacent cells on the circle.

Clockwise: add a sharp (up a fifth). Counterclockwise: add a flat (down a fifth). At the bottom, enharmonic keys join the two branches.

C major / A minor

Key signature: no sharps or flats
Relative: A minor, a minor third below; leading tone G♯ added as an accidental
Closely related keys: A minor, F major, G major, D minor, E minor
Landmark: the model scale, no accidentals

Exercisein the method's spirit

Analyze the key scheme of this fragment: identify the modulation, the exact point where it happens, and the note that brings it about.

Modulation changes the key inside a piece. In the next lesson, you'll move a whole piece into a new key: that is transposition.

Check your understanding

6 questions

What is modulation?

Which note most often brings about a modulation?

In F major, a B♮ most likely announces:

In D major, a C♮ most likely announces:

For a passing key, how are the new sharps or flats written?

Going from 2 sharps to 1 flat in the key signature, what must you write at the change?

A lesson is completed automatically at 70% on the quiz. You can also mark it yourself.

A question, a mistake, a word about this lesson? Write to us.