The Functions of Chords: For Pop, Jazz, and Modern Styles
by Peter Lynn Sessions
Category: Music

Pete Sessions has written a revolutionary book on music theory. This book develops a model of the listener that explains how the listener interprets the chords in a progression. It develops the theory, covering expectation and return, categories of chord types, movement and finality, and mood and stability. It then applies the theory to pop, jazz, and modern music. Why is it that many chord progressions in modern music fail to ignite listener interest? What makes other chord progressions popular? In The Functions of Chords, the author analyzes chords and their impact on the listener in various progressions. His analysis provides a surprising answer to these questions: The function of chords is to convey information. The book explains the sources of the information in chords and what the listener does with that information---in terms every composer and musician will understand. The key to the author's analysis is a new focus on the listener. The author builds a model of the listener to predict how chord progressions affect the audience. He then takes the next step and challenges the composer to heed the listener's response. He provides theoretical explanations of expectation and return, mood, and stability, tritones and conflict, movement and finality. He develops chord types that allow a composer to develop an algorithm. The Functions of Chords not only presents a new theory, but shows how you can apply this theory to pop, jazz, or modern music. The theory can be applied to algorithmic composition and may shed light on the physiology of musical perception.