semicord

Ab7 Ab dominant seventh chord

Notes
Ab C Eb Gb
Formula
1 3 5 b7
Semitones
0 4 7 10 above the root
Also written
G#7 (G# B# D# F#)
Other symbols
Abdom7

Ab to C is a major third (4 semitones), C to Eb is a minor third (3 semitones), Eb to Gb is a minor third (3 semitones). A dominant seventh is a major triad plus a minor seventh (Gb, 10 semitones above Ab). It is the V chord that leads back home, and the basic chord of the blues.

Ab7 on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C#4Eb4F#4Ab4Bb4C#5Eb5Gb5Ab5Bb5C4AbCC5EbGb

Root position from Ab4: Ab4, C5, Eb5, Gb5. Middle C is C4.

Ab7 on the guitar

Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has Ab as its lowest note.

4frAbAbEbEbGbGbCCEbEbAbAb
E-shape barre, root on the E string at fret 4
4 6 4 5 4 4 (low E to high e)
Sounds Ab2 Eb3 Gb3 C4 Eb4 Ab4
11fr×AbAbEbEbGbGbCCEbEb
A-shape barre, root on the A string at fret 11
x 11 13 11 13 11 (low E to high e)
Sounds Ab3 Eb4 Gb4 C5 Eb5

The barre shapes are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play dominant seventh chords on other roots.

Inversions of Ab7

An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.

PositionNotes, bass firstNamedListen
Root positionAb C Eb GbAb7
1st inversionC Eb Gb AbAb7/C
2nd inversionEb Gb Ab CAb7/Eb
3rd inversionGb Ab C EbAb7/Gb

Where Ab7 fits

Ab7 is V7 in Db major, V7 in C# minor (where it is spelled G#7). Its C and Gb are a tritone apart (6 semitones). In Db major the C usually rises a half step to Db and the Gb falls a half step, which is why Ab7 pulls so strongly towards Db.