What Are Secondary Dominants in Music, and How Do V/V and V/ii Work?

Secondary Dominants: How to Create Temporary Harmonic Gravity

In tonal music, the dominant chord has a particularly strong relationship with the tonic. It creates tension and expectation, encouraging the music to resolve to its tonal centre.

But the dominant does not have to lead only to the main tonic.

A composer can temporarily treat another chord as a tonic and introduce its own dominant. This technique is called a secondary dominant.

Secondary dominants expand the harmonic vocabulary of a key. They create additional points of tension and allow ordinary diatonic progressions to acquire stronger direction.

1. What Is a Secondary Dominant?

A secondary dominant is a dominant-function chord that resolves to a diatonic chord other than the main tonic.

In C major, the dominant is G major or G7, which resolves to C major.

But consider D minor, the supertonic chord of C major.

The dominant of D minor is A major or A7.

A major contains:

A – C-sharp – E

C-sharp is not part of the C major scale. It is introduced because it functions as the leading tone of D.

When A major resolves to D minor, the C-sharp moves upward to D, creating a strong local resolution.

The chord is labelled:

V/ii

This means the dominant of the second-degree chord.

The slash indicates the chord that the dominant is expected to resolve to.

2. Why Secondary Dominants Work

A secondary dominant temporarily strengthens a chord by giving it its own dominant.

The altered note is particularly important.

In the example A major to D minor, C-sharp creates a leading-tone relationship with D.

The listener hears a local expectation of resolution, even though D is not the tonic of the overall key.

This gives the progression an additional level of harmonic direction.

Instead of every chord being approached through the same diatonic relationships, individual chords can receive their own dominant preparation.

3. Secondary Dominants in C Major

Several chords in C major can be approached through their own dominant chords.

The secondary dominant may be a major triad or a dominant seventh chord.

The dominant seventh often creates an even stronger sense of direction because it includes an additional tendency tone.

The leading-tone chord itself, vii°, is another possibility, but it is a different chord type and is treated separately in the article on secondary leading-tone chords.

4. Example: Strengthening the Supertonic

Begin with a simple progression in C major:

C – Dm – G7 – C

The D minor chord is approached directly from C major.

Now introduce its secondary dominant:

C – A7 – Dm – G7 – C

The A7 chord contains C-sharp, which resolves to D in the following D minor chord.

The progression now contains two dominant relationships:

• A7 → Dm
• G7 → C

The first is a local dominant resolution. The second is the main cadence in C major.

This creates a more directed progression without changing the overall key.

5. The Dominant of the Dominant

One particularly common secondary dominant is V/V — the dominant of the dominant.

In C major, the dominant chord is G major.

Its own dominant is D major.

D major contains F-sharp, which resolves upward to G.

A simple example is:

C – D7 – G7 – C

The D7 chord strengthens the arrival on G7, which then resolves to C.

This creates a chain of dominant relationships.

It is one of the most familiar ways of intensifying a progression before a cadence.

6. Secondary Dominants and Modulation

Secondary dominants can contribute to modulation, but their presence alone does not prove that a modulation has taken place.

Consider D7 in C major.

It may function as V/V, temporarily strengthening G major before the music returns to C.

But if the progression continues in G major, emphasises its tonic and confirms it with a cadence, the same D7 may become part of a genuine modulation.

The distinction depends on the larger context.

Secondary dominants create temporary tonal gravity. Modulation establishes a new tonal centre.

7. Voice Leading in Secondary Dominants

The chromatic notes introduced by secondary dominants should be handled with attention to their resolution.

In A7–D minor, the notes can move as follows:

• C-sharp → D
• G → F or A, depending on the voicing
• E → F or D
• A → A or another suitable chord tone

The exact arrangement depends on the preceding and following chords.

The central principle is that the chromatic leading tone should normally resolve toward the root of its temporary tonic chord.

Good voice leading makes the secondary dominant sound like a natural part of the progression rather than an unrelated chromatic interruption.

8. Secondary Dominants in Jazz, Pop and Electronic Music

In jazz, secondary dominants are part of the basic harmonic vocabulary. They frequently appear before diatonic chords and can create extended chains of dominant movement.

In pop music, they can strengthen a chorus arrival, prepare a new section or add harmonic interest to an otherwise simple progression.

In film scoring, they can create anticipation before a particular chord or melodic event.

Electronic composers can use secondary dominants to introduce controlled chromatic movement into sequences and generative systems.

A modular or MIDI-based system might select a diatonic chord and then generate its dominant as a preparation. The resulting chromatic note creates a local resolution without requiring a complete change of key.

9. Practical Exercise

Write a progression in C major:

C – Dm – G7 – C

Now add secondary dominants in three places:

1. Use A7 before D minor: V/ii.
2. Use D7 before G7: V/V.
3. Use E7 before A minor: V/vi.

Try combining two of them:

C – A7 – Dm – D7 – G7 – C

Listen to the difference between the original progression and the chromatically intensified version.

Notice how the secondary dominants make the arrival of individual chords more pronounced.

Conclusion

Secondary dominants allow composers to create temporary dominant relationships within an established key.

They introduce chromatic notes that strengthen individual chords and provide additional harmonic direction.

Their power comes from the familiar dominant-to-tonic relationship being applied to chords other than the main tonic.

Used carefully, secondary dominants can make a simple progression more expressive, more directional and more harmonically varied without requiring a full modulation.

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