modulation explained
theorymod-yoo-LAY-shun
A comprehensive guide to the process of changing from one key to another within a piece of music.
Modulation is the technique of shifting from one key to another during a piece, creating variety, drama, and emotional movement. The simplest and most common modulation moves to a closely related key — from C major to G major (the dominant), for example. Pivot chord modulation uses a chord that exists in both the old and new key as a bridge between them. Direct modulation simply jumps to the new key without preparation. The "truck driver's modulation" — a sudden upward shift of a half step or whole step, often before the final chorus of a pop song — creates an instant energy boost. In classical music, modulation is a primary tool for large-scale form: sonata form depends on the movement from tonic to dominant in the exposition and the return to tonic in the recapitulation. Frequent, adventurous modulation characterises the Romantic period.
The "truck driver's modulation" — named for its unsubtle, brute-force quality — has been used in hundreds of pop songs, from Whitney Houston's "I Wanna Dance with Somebody" to Bon Jovi's "Livin' on a Prayer."