semicord

Bb13 Bb dominant thirteenth chord

Notes
Bb D F Ab C Eb G
Formula
1 3 5 b7 9 11 13
Semitones
0 4 7 10 14 17 21 above the root
Also written
A#13 (A# C## E# G# B# D# F##)
Other symbols
Bbdom13

Bb to D is a major third (4 semitones), D to F is a minor third (3 semitones), F to Ab is a minor third (3 semitones), Ab to C is a major third (4 semitones), C to Eb is a minor third (3 semitones), Eb to G is a major third (4 semitones). A dominant seventh with the thirteenth, G, on top. The full chord has seven notes and a guitar has six strings, so players keep the root, the third D, the seventh Ab and the thirteenth G, and leave out the fifth, the ninth and above all the eleventh Eb, which clashes with the third. The thirteenth is the sixth an octave up; it is a 13 and not a 6 chord because the seventh is there.

Bb13 on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C6D6E6F6G6A6B6C#4Eb4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5C#6Eb6F#6Ab6Bb6C4BbC5DFAbCC6EbG

Root position from Bb4: Bb4, D5, F5, Ab5, C6, Eb6, G6. Middle C is C4.

Bb13 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 Bb as its lowest note.

×BbBb×AbAbDDGG
A-shape, root on the A string at fret 1
x 1 x 1 3 3 (low E to high e)
Sounds Bb2 Ab3 D4 G4, fifth, ninth and eleventh left out
6frBbBb×AbAbDDGG×
E-shape, root on the E string at fret 6
6 x 6 7 8 x (low E to high e)
Sounds Bb2 Ab3 D4 G4, fifth, ninth and eleventh left out

The E-shape and A-shape grips 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 thirteenth chords on other roots.

Inversions of Bb13

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 positionBb D F Ab C Eb GBb13
1st inversionD F Ab C Eb G BbBb13/D
2nd inversionF Ab C Eb G Bb DFm13 (also read as Bb13/F)
3rd inversionAb C Eb G Bb D FBb13/Ab
4th inversionC Eb G Bb D F AbBb13/C
5th inversionEb G Bb D F Ab CBb13/Eb
6th inversionG Bb D F Ab C EbBb13/G

Where Bb13 fits

Bb13 is V13 in Eb major. Played with its third, seventh and thirteenth (D, Ab, G) over the root, it is the standard dominant chord of jazz and soul, resolving to Eb.