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Chord · A Dominant 11th

A11 Chord

A11 is A, C#, E, G, B and Ddense; usually voiced rootless.

Hear it

A11 on every instrument

The same 6 notes, 2 sets of hands. Open a diagram for alternate shapes, audio and the mistakes to avoid.

×EADGBE
Guitar2 voicings
CDEFGAB
Piano2 voicings

What A11 is made of

A11 (A eleventh) is built from the notes A, C#, E, G, B, D, with the interval pattern 1, 3, 5, b7, 9, 11.

Stack 1, 3, 5, b7, 9 and 11 on a root of A and you get A, C#, E, G, B and D. That interval recipe is what makes the chord an eleventh chord — move the same shape to another root and the character travels with it, which is why C11 sounds like a transposed A11.

Dominant 11th: Dense; usually voiced rootless.

Spelling: the notes above are written the way a score would write them, not simplified to the nearest piano key. That is why this chord is spelled with C rather than its enharmonic equivalent.

Keys that contain A11

All 6 notes sit inside the scale of 2 keys. The roman numeral marks the degree the chord is rooted on.

Other chords on A

Same root, different colour.

The same eleventh shape, moved

The identical interval recipe, built on other roots.

Questions people ask about A11

What notes are in the A11 chord?
A11 is made of A, C#, E, G, B and D — the 1, 3, 5, b7, 9 and 11 degrees of an eleventh chord built on A.
What keys use the A11 chord?
Every note of A11 belongs to 2 keys: D Major (V), B Minor (VII). The roman numeral is the scale degree the chord is rooted on.
How do you play A11 on guitar and piano?
This page shows A11 on guitar and piano — 4 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.

Learn the theory behind it

Why A11 behaves the way it does — the guides that explain the chord instead of just spelling it.

Functional Harmony: Three Roles, One EngineWhat a seventh chord is for — tension, resolution, and the seat it takes in the key.6 min readThe 12-Bar Blues — Three Chords, A Century of HitsSeventh chords are the whole sound of the blues. Twelve bars is where to hear it.7 min read