Modulating Period

[Back to Choosing a Phrase Structure]

The modulating period starts the same as the ordinary period (which you should try first) but the consequent phrase finishes with a perfect cadence in a new key, usually the relative major or dominant.

  • ANTECEDENT
    • Basic idea (2 bars)  – this is the melody you wrote in Stage One
    • Contrasting idea (2 bars) – must end on V
  • CONSEQUENT
    • Repetition of Basic Idea (2 bars) – exact repetition of first two bars
    • Contrasting idea (2 bars) – as before but ending on a perfect cadence in a new key (modulate using a pivot chord as explained below the example)

Haydn Op. 64 No. 4, third movement

Modulating Period Haydnop64n4iii

In the consequent phrase, Haydn moves from C major to its dominant (G) via a pivot chord. The A minor chord (shown in the box) is chord vi in C major and also chord ii in G major – this chord provides a pivot (or a common chord) between the two keys.

The two most common pivot chords between the tonic and dominant keys are as follows:

Tonic   |   Dominant
    I        |      IV
vi        |     ii