Table of Contents
Music theory is filled with concepts that help musicians understand harmony and chord progressions. Two such concepts are Extended Dominant Prolongation and Secondary Dominants. Although they are related, they serve different functions in musical composition and analysis.
What Are Secondary Dominants?
Secondary dominants are chords that temporarily emphasize a non-tonic chord by treating it as a temporary tonic. They are often used to create tension and drive the harmony forward. For example, in the key of C major, the chord D7 functions as a secondary dominant leading to G major, the V chord.
This technique effectively highlights a specific chord within a progression, making it sound more dynamic and expressive. Secondary dominants are usually notated with a slash or Roman numeral indicating the target chord, such as V7/ii.
What Is Extended Dominant Prolongation?
Extended dominant prolongation involves extending the duration of a dominant chord beyond its usual resolution point. This prolongation can span multiple measures, creating a sense of anticipation and tension. It often occurs in jazz, classical, and popular music to build momentum before resolving.
For example, a composer might hold a V7 chord for several beats or measures, delaying the resolution to the tonic. This technique emphasizes the dominant function and heightens the listener’s expectation of resolution.
Differences and Similarities
While both concepts involve the dominant function, they differ in purpose and execution:
- Secondary Dominants are specific chords that temporarily tonicize a chord other than the tonic.
- Extended Dominant Prolongation is the sustained use of a dominant chord to build tension over time.
- Secondary dominants are usually brief and serve as passing or transitional chords.
- Extended prolongation involves holding a dominant chord longer than usual, often for expressive or structural reasons.
In Summary
Understanding the difference between extended dominant prolongation and secondary dominants helps musicians craft more expressive and structurally sound compositions. Secondary dominants add color and surprise, while extended prolongation builds suspense and emotional intensity.