Melodic Phrases and Harmonic Cadences

Motives, Phrases, and Periods

A composer creates a piece by deciding what the building blocks will be, how they will be developed and extended, and what form the piece will take.  The smallest of these building blocks is the motive.

Motives are typically combined and varied to create a phrase.  The phrase might be referred to as the smallest structural unit that is concluded with a cadence.  Two or more phrases together can be used to build a period, if the cadence in the middle is weaker or less conclusive than the final cadence.

Types of Cadences

A harmonic cadence is a sequence of chords that end a phrase.  The function of the last two chords define the cadence.  Common types of cadences are listed below.

PAC – Perfect Authentic Cadence

IAC – Imperfect Authentic Cadence

HC – Half Cadence

DC – Deceptive Cadence

PC – Plagal Cadence