D7

D Dominant 7th — the engine of harmonic motion — the tritone between its third and seventh drives resolution down a fifth.

The keys
C4C5C6
D – F♯ – A – C
What's inside D7
NoteInterval from rootDegree
DRoot1
F♯Major 3rd3
APerfect 5th5
CMinor 7thb7
Inversions
PositionKeys (low → high)
Root positionD4 – G♭4 – A4 – C5
1st inversionG♭4 – A4 – C5 – D5
2nd inversionA4 – C5 – D5 – G♭5
3rd inversionC5 – D5 – G♭5 – A5
A working voicing

Split the chord between two hands the way working players do — a solid shell low down, the colour tones up top:

HandKeys
Left (shell)D2 – C3
Right (colour)G♭4 – A4
Where D7 lives

Resolving down a fifth

D7 → G

The defining dominant move: the tritone inside this chord releases onto the chord a fifth below.

In a ii–V–I

Am7 → D7 → Gmaj7

This chord as the V — the engine of the most-used cadence in music.

Put D7 under your fingers

Hear every voicing, see the keys light up, and drill it in the interactive Chord & Voicing Lab.

Open the Chord & Voicing Lab →
Dominant 7th in every key
C7 C♯7 E♭7 E7 F7 F♯7 G7 A♭7 A7 B♭7 B7