The A♭ Dominant 7th chord is a four-note chord made up of A♭, C, E♭, and G♭. It is built from a root, major third, perfect fifth, and minor seventh.
Construction
| Note | Interval | Degree |
|---|---|---|
| A♭ | Root | 1 |
| C | Major 3rd | 3 |
| E♭ | Perfect 5th | 5 |
| G♭ | Minor 7th | ♭7 |
A♭ Dominant 7th Inversions
| Position | Notes |
|---|---|
| Root Position | A♭ – C – E♭ – G♭ |
| 1st Inversion | C – E♭ – G♭ – A♭ |
| 2nd Inversion | E♭ – G♭ – A♭ – C |
| 3rd Inversion | G♭ – A♭ – C – E♭ |
Key Signature
A dominant chord points home to the key a fifth below its root: the A♭ Dominant 7th is the V (dominant) of Db Major, so the relevant key signature is that key’s — 5 flats (B♭, E♭, A♭, D♭, G♭). Spelled as a scale, these notes are Ab 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 D♭ Major
These are the triads built on each degree of the D♭ major scale:
How A♭ 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 A♭ Dominant 7th sits diatonically across the common keys:
- In D♭ major, A♭ Dominant 7th is the V chord — the dominant.
- In B♭ minor, A♭ Dominant 7th is the ♭VII chord — a mediant / color chord.