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