Modulation Chapter 15
Modulation • Process that results in a shift of tonal center • Commonly called a key change
Closely Related Keys • Keys that differ by no more than one accidental in the key signature and the relative major or minor • Example: a minor • Closely related keys are: CM, em, dm, GM, and FM
Types of Modulations • Common Chord Modulation • Uses a pivot chord that belongs to both keys • Example: vi in DM also functions as the ii in AM • Phrase Modulation • One phrase cadences in the original key • The next phrase begins in the new key • Chromatic Modulation • One chord tone is raised by ½ step in one voice to introduce the new key • No common chord is used
Harmonizing Modulating Melodies • Identify the possible keys based on the key signature and its closely related keys • Identify the cadences in those possible keys • Identify the possible chords for each melody note • Choose the harmonic progression that makes the most sense • Identify the harmonic rhythm • Write a bass line • Add alto and tenor lines and non-harmonics
Harmonizing a Modulating Melody • Things to consider: • 1. Circle progression is important in establishing the key, especially after a modulation • 2. Try to use a common chord when possible. • 3. Start with the cadence and move backward through the melody.