Secondary Dominants - Adding Color to Harmony
Have you ever noticed a chord in a song that *sounds* right but isn't actually in the key? Often, that chord is a Secondary Dominant. It's one of the most powerful tools for adding sophistication and "pull" to your harmony.
The Concept of the Dominant
In any key, the most powerful chord is the V chord (the Dominant). In C Major, that's G Major. It wants to resolve back to C. A secondary dominant takes this "pull" and applies it to a chord *other* than the tonic.
The "Five of Five" (V/V)
The most common secondary dominant is the "V of V." Here is how to find it in 3 steps:
- Find your V chord (In C Major, that's G).
- Imagine G is now your "Home." What is the V chord of G? (It's D Major).
- Use that D Major chord in your C Major progression.
Progressions often look like this: C → D → G → C. The D chord feels like it "sets up" the G chord perfectly.
Spotting Accidentals
Secondary dominants will always have at least one note that isn't in your starting key (an accidental). In the example above, D Major has an F#, which isn't in the C Major scale. That's what gives it that "bright" harmonic lift.
Secondary Dominants for Other Chords
You can use this for almost any chord in the scale:
- V/ii: Leading to the 2nd chord.
- V/vi: Leading to the 6th chord (very popular in emotional pop bridges).
- V/IV: Leading to the 4th chord.
Why Use Them?
Secondary dominants make your music sound more professional. They create temporary centers of gravity that keep the listener's ear engaged. It’s like taking a brief detour through a different key before returning home.