Secondary Dominants
A secondary dominant is a dominant chord that targets a diatonic chord other than the tonic. In C major, A7 is V of ii because it creates a temporary dominant pull toward Dm. Build the target first, then find its dominant.
- dominant of a diatonic target
- introduces a chromatic leading tone
- written V/target
How do you build a secondary dominant?
- Choose a targetin C major, choose ii: Dm.
- Treat its root as temporary tonicthe target note is D.
- Find its dominanta fifth above D is A.
- Build A7A-C sharp-E-G resolves to D-F-A.
What does V of something mean?
V/ii reads “five of two.” The numeral after the slash names the target; the V before it names the dominant relative to that target.
| Symbol in C major | Chord | Target | Chromatic note and motion |
|---|---|---|---|
| V/ii | A7 | Dm | C sharp rises to D |
| V/IV | C7 | F | B flat falls to A |
| V/V | D7 | G | F sharp rises to G |
| V/vi | E7 | Am | G sharp rises to A |
V/iii is B7 targeting Em and is possible, though less common in basic tonal progressions. A diminished target such as vii° is rarely tonicized because it does not provide a stable local arrival.
Why does the seventh chord create a stronger target?
A major triad supplies a temporary leading tone. Adding the minor seventh creates a tritone that resolves into the target chord.
In A7-Dm, C sharp rises to D and G commonly falls to F. Those two voices form the same dominant mechanism heard in G7-C, transposed to a temporary destination.
The dominant seventh is common, but the triad alone can work. A major resolving to D minor already contains the decisive C sharp.
How is a secondary dominant different from a borrowed chord?
Secondary dominant. Its altered notes create dominant voice leading into a specific target. A7 in C major points to Dm.
Modal interchange. The chord is borrowed from a parallel mode and often acts as color or predominant motion. Fm in C major comes from C minor and commonly returns toward C.
Chromatic mediant. A major or minor chord a third away may share a common tone and move by semitone without functioning as a dominant.
Follow the resolution before naming the chord. A D7 that resolves to G is V/V; a D-major color that returns directly to C may be heard as modal or chromatic color.
What is tonicization?
Tonicization gives one non-tonic chord a brief sense of arrival. A7-Dm in a C-major phrase can make Dm sound locally important for one beat or one bar while C remains the overall tonic.
Modulation establishes a new key strongly enough that its tonic governs a longer passage. Repeated cadences, melodic emphasis and sustained use of the new scale support that change.
One secondary dominant does not automatically create a modulation. Listen to what happens after the target: does the music return to the original system or continue in the new one?
Where can secondary dominants go wrong?
- Missing target
A dominant that never reaches or clearly redirects from its target may sound unexplained.
- Hidden altered note
The chromatic leading tone creates much of the effect. Place it in an audible voice and resolve it clearly.
- Incorrect spelling
V/V in C uses F sharp because that note leads to G. Writing G flat hides the scale-degree motion.
- Automatic chains
A sequence of applied dominants can be effective, but each additional chord increases harmonic activity and changes the style.
How do chains of dominants work?
Start from the final target and work backward by descending fifths. In C major, E7-A7-D7-G7-C creates a chain in which every chord acts as dominant of the next.
The roots move E-A-D-G-C. Each resolution confirms a local target for only a moment before that target becomes another dominant.
This pattern is common in jazz, ragtime, gospel and turnarounds. Use smooth thirds and sevenths to keep the chromatic sequence connected.
How should you practice secondary dominants?
- Play the diatonic versionC-Am-Dm-G-C.
- Alter one chordchange Am to A7 and follow C sharp to D.
- Target another degreeinsert D7 before G or E7 before Am.
- Label the target firstsay “V of five” before naming D7.
Keep going
Everything in harmony
- Secondary Dominants
- Modal Interchange
- Chromatic Harmony
- Modulation
- Modal Harmony
- Harmonic Sequences