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