How to Construct and Recognize Secondary Dominants in Progressions

Understanding secondary dominants is essential for musicians and students studying music theory. These chords add color and tension to progressions, making music more interesting and dynamic. This article explains how to construct and recognize secondary dominants in various chord progressions.

What Are Secondary Dominants?

Secondary dominants are chords that function as the dominant (V) of a chord other than the tonic. They temporarily emphasize a specific chord within a progression, creating a sense of tension and release. For example, in the key of C major, the V of D minor (which is D major or D7) acts as a secondary dominant to D minor.

How to Construct Secondary Dominants

Constructing a secondary dominant involves identifying the target chord and building a V chord that leads into it. Follow these steps:

• Identify the target chord you want to emphasize.
• Determine its root note.
• Build a major triad or dominant seventh chord a fifth above the target root.
• Use this chord as the secondary dominant before the target chord.

For example, to create a secondary dominant for D minor (ii chord in C major):

• Target chord: D minor (D)
• Root note: D
• Build a V chord a fifth above D: A major or A7
• Place A7 before D minor in the progression

How to Recognize Secondary Dominants

Recognizing secondary dominants involves listening for chords that create a temporary sense of tension and lead strongly into a specific chord. Look for these clues:

• The chord is a major or dominant seventh chord that doesn't belong to the key's diatonic set.
• It resolves quickly to a diatonic chord, often a minor or major chord.
• The chord functions as a V of another chord in the progression.
• In notation, it is often labeled with a Roman numeral followed by a slash and the target chord, e.g., V/ii or V/V.

For example, in C major, an A7 chord resolving to D minor is a secondary dominant, labeled as V/ii. Recognizing this pattern helps musicians understand the harmonic function and enhances improvisation and composition skills.