A flat Dominant Thirteenth Chord (A♭13)

1Composition: what it contains

A♭ – C – E♭ – G♭ – B♭ – F

Symbol

A♭13

Also written

A♭13, A♭7(13), A♭dom13

Formula

1 3 5 ♭7 9 13

Same sound as

G♯13

2Appearance: diagrams and sound

On the guitar

On the ukulele

On the piano

On the staff

On bass and as an arpeggio

3Indications: what it is used for

A staple of jazz, big-band swing, blues, funk, soul and gospel on dominant chords: the V13 in a ii–V–I, I13 and IV13 in jazz blues, and funk vamps. It includes the ninth implicitly in many voicings and usually omits the eleventh (which clashes with the third). Mixolydian is the scale; the thirteenth is the same note as the sixth degree. It can replace any dominant seventh when the melody contains the natural thirteenth or ninth.

4Dosage: how to practise it

On guitar, learn the shape rooted on the sixth string (root, ♭7, 3, 13) and the shape rooted on the fifth string; practise sliding them in from a half step below. On piano, play rootless voicings ♭7-9-3-13 and 3-13-♭7-9 in the left hand. Practise ii9–V13–Imaj9 in all keys at 80–160 BPM with a swing feel. Ten minutes daily. On bass, outline 1-3-5-♭7 and resolve to the next chord. Practise a twelve-bar blues with all dominant chords as thirteenths, comparing them with plain dominant sevenths and ninths.

5Warnings and common mistakes

Do not play the eleventh in a dominant thirteenth chord: it clashes with the major third, so omit it. Do not confuse 13 with 6 (no seventh) or with maj13 (major seventh). The essential notes are the third, flat seventh and thirteenth; the root and fifth can be omitted. If the melody holds the flat thirteenth (for example in minor keys), use 7♭13 or the altered sound instead.

6Interactions with chords, scales and keys

Inversions

• Inversion 1 · A♭13/C · C – E♭ – G♭ – B♭ – F – A♭ Play
• Inversion 2 · A♭13/E♭ · E♭ – G♭ – B♭ – F – A♭ – C Play
• Inversion 3 · A♭13/G♭ · G♭ – B♭ – F – A♭ – C – E♭ Play
• Inversion 4 · A♭13/B♭ · B♭ – F – A♭ – C – E♭ – G♭ Play
• Inversion 5 · A♭13/F · F – A♭ – C – E♭ – G♭ – B♭ Play

Scales to play over A♭13

• A flat Mixolydian Mode
• A flat Lydian Dominant Scale
• A flat Bebop Dominant Scale

7Other presentations available

The same chord from every note

C13 C♯13 D13 E♭13 E13 F13 F♯13 G13 A13 B♭13 B13

Other chords on A♭

A♭ A♭m A♭dim A♭aug A♭sus2 A♭sus4 A♭5 A♭6 A♭m6 A♭7 A♭maj7 A♭m7 A♭m7♭5 A♭dim7 A♭m(maj7) A♭7sus4 A♭add9 A♭m(add9) A♭6/9 A♭9 A♭maj9 A♭m9 A♭11 A♭m11 A♭7♭9 A♭7♯9 A♭7♯5 A♭7♭5