semicord

Db7 Db dominant seventh chord

Notes
Db F Ab Cb
Formula
1 3 5 b7
Semitones
0 4 7 10 above the root
Also written
C#7 (C# E# G# B)
Other symbols
Dbdom7

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

Db7 on the piano

C4D4E4F4G4A4Cb4C5D5E5F5G5A5B5Db4Eb4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5C4DbFAbCbC5

Root position from Db4: Db4, F4, Ab4, Cb4. Middle C is C4.

Db7 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 Db as its lowest note.

4fr×DbDbAbAbCbCbFFAbAb
A-shape barre, root on the A string at fret 4
x 4 6 4 6 4 (low E to high e)
Sounds Db3 Ab3 Cb3 F4 Ab4
9frDbDbAbAbCbCbFFAbAbDbDb
E-shape barre, root on the E string at fret 9
9 11 9 10 9 9 (low E to high e)
Sounds Db3 Ab3 Cb3 F4 Ab4 Db5

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 Db7

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 positionDb F Ab CbDb7
1st inversionF Ab Cb DbDb7/F
2nd inversionAb Cb Db FDb7/Ab
3rd inversionCb Db F AbDb7/B

Where Db7 fits

Db7 is V7 in Gb major, V7 in F# minor (where it is spelled C#7). Its F and Cb are a tritone apart (6 semitones). In Gb major the F usually rises a half step to Gb and the Cb falls a half step, which is why Db7 pulls so strongly towards Gb.