semicord

Bb11 Bb dominant eleventh chord

Notes
Bb D F Ab C Eb
Formula
1 3 5 b7 9 11
Semitones
0 4 7 10 14 17 above the root
Also written
A#11 (A# C## E# G# B# D#)
Other symbols
Bbdom11

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). All six notes stacked in thirds, 1 3 5 b7 9 11. The eleventh, Eb, sits a minor ninth above the third D and clashes with it, so in practice the third is left out: Bb F Ab C Eb is how Bb11 is usually played, the same notes as Bb9sus4. Leave out the fifth as well and the engine hears Ab/Bb instead (Bb Ab C Eb), so the guitar shapes here keep F.

Bb11 on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C6D6E6F6G6A6B6C#4Eb4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5C#6Eb6F#6Ab6Bb6C4BbC5DFAbCC6Eb

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

Bb11 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.

×BbBbEbEbAbAbCCFF
A-shape barre, root on the A string at fret 1
x 1 1 1 1 1 (low E to high e)
Sounds Bb2 Eb3 Ab3 C4 F4, third left out
6frBbBbEbEbAbAbEbEbFFCC
E-shape barre, root on the E string at fret 6
6 6 6 8 6 8 (low E to high e)
Sounds Bb2 Eb3 Ab3 Eb4 F4 C5, third 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 eleventh chords on other roots.

Inversions of Bb11

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 EbBb11
1st inversionD F Ab C Eb BbBb11/D
2nd inversionF Ab C Eb Bb DFm13 (also read as Bb11/F)
3rd inversionAb C Eb Bb D FBb11/Ab
4th inversionC Eb Bb D F AbBb11/C
5th inversionEb Bb D F Ab CBb11/Eb

Where Bb11 fits

Bb11 is V11 in Eb major. The eleventh, Eb, is the same note as the fourth of a sus chord and wants to fall to the third D; that is why the third is usually left out, and why Bb11 works as a softer V that delays the pull home. It often moves to Bb7 before the tonic.