The D♭ Dominant 7th chord is a four-note chord made up of D♭, F, A♭, and C♭. It is built from a root, major third, perfect fifth, and minor seventh.
Construction
| Note | Interval | Degree |
|---|---|---|
| D♭ | Root | 1 |
| F | Major 3rd | 3 |
| A♭ | Perfect 5th | 5 |
| C♭ | Minor 7th | ♭7 |
D♭ Dominant 7th Inversions
| Position | Notes |
|---|---|
| Root Position | D♭ – F – A♭ – C♭ |
| 1st Inversion | F – A♭ – C♭ – D♭ |
| 2nd Inversion | A♭ – C♭ – D♭ – F |
| 3rd Inversion | C♭ – D♭ – F – A♭ |
Key Signature
A dominant chord points home to the key a fifth below its root: the D♭ Dominant 7th is the V (dominant) of Gb Major, so the relevant key signature is that key’s — 6 flats (B♭, E♭, A♭, D♭, G♭, C♭). Spelled as a scale, these notes are Db Mixolydian.
Order of flats
Flats are added in a fixed order — the reverse of the sharp order. Each new flat key adds the next flat on the list.
Mnemonic: Battle Ends And Down Goes Charles’ Father
Chords in the Key of G♭ Major
These are the triads built on each degree of the G♭ major scale:
How D♭ Dominant 7th functions in a key
The same chord takes on a different harmonic role depending on the key it appears in. Here is where D♭ Dominant 7th sits diatonically across the common keys:
- In G♭ major, D♭ Dominant 7th is the V chord — the dominant.
- In E♭ minor, D♭ Dominant 7th is the ♭VII chord — a mediant / color chord.