Secondary dominants are a powerful tool in harmony that add richness and complexity to traditional diatonic progressions. By temporarily treating a diatonic chord as a tonic, secondary dominants create a stronger sense of movement and resolution. This is achieved by using the dominant chord of the intended chord's key.
- Secondary dominants act as temporary dominants for diatonic chords.
- They enhance harmonic interest and smooth transitions.
- Function as the V chord of another chord within the key.
When to Use
Secondary dominants are commonly employed when a composer or performer wants to add tension and color to a progression. They are particularly effective before a chord that requires stronger resolution, such as the ii, vi, or any chord leading to a cadence. By using a secondary dominant, the musician can enhance the chord's pull towards resolution, making the music more engaging.
- Use before chords needing stronger resolution.
- Commonly applied to ii and vi chords.
- Adds tension and color to progressions.
Example: Key of C
In the key of C major, to tonicize the chord A minor (vi), we can use its secondary dominant, which is E7 (V/vi). This introduces G# (the leading tone to A), creating a stronger resolution to A minor. The progression would be C - G - E7 - Am.
| Chord Function | Chord | Notes |
|---|---|---|
| Tonic | C | C - E - G |
| Dominant | G | G - B - D |
| Secondary Dominant | E7 | E - G# - B - D |
| Tonic | Am | A - C - E |
Common Patterns
When using secondary dominants, several common patterns emerge. One favorite is the use of secondary dominants to lead into minor chords, where the added tension from the dominant seventh chord strongly resolves to the minor tonic. This pattern not only enriches the harmonic vocabulary but also helps establish temporary key areas within a piece.
| Chord | Function | Progression Example |
|---|---|---|
| V/ii | Tonicizes ii | C - D7 - Em |
| V/vi | Tonicizes vi | C - E7 - Am |
| V/iii | Tonicizes iii | C - B7 - Em |
| V/V | Tonicizes V | C - G7 - D |
| V7/ii | Tonicizes ii (with 7) | C - D7 - Em |