7b9 chords
The 7th flat 9th chord a.k.a. the 7th minus 9th chord is an alternate seventh chord. This chord is a dominant seventh with an added flattened ninth.
By comparing C7 with C7b9, we can see that the notes change from C, E, G, Bb to C, E, G, Bb, Db.
The most common way to play the flat nine chord is by using the movable shape presented in the diagrams below. You have the option to play it with all four fingers or to lay the index finger over the frets behind and use three fingers in total.
7b9
C7b9
C#7b9
D7b9
D#7b9
E7b9
F7b9
F#7b9
G7b9
G#7b9
A7b9
A#7b9
B7b9
Comments
C7b9 can also be played as x32320. The E7b9 can also be played with one or two open strings.
The seventh flat nine chord can also be written with a minus instead of the flat symbol, such as
C7-9.
Chord formula
The seventh flat ninth is built with the formula 1-3-5-b7-b9. This includes the root (1), the third (3), the perfect fifth (5), the minor seventh (b7) and a flattened ninth (b9).
Chord construction
C7b9 x - x - C - E - Bb - DbC#7b9 x - x - C# - F - B - D
D7b9 x - x - D - Fb - C - Eb
D#7b9 x - x - D# - G - Cb - E
E7b9 x - x - E - Gb - D - F
F7b9 x - x - F - A - Db - Gb
F#b7b9 x - x - F# - Ab - E - G
G7b9 x - x - G - B - F - Ab
G#7b9 x - x - G# - C - Fb - A
A7b9 x - x - A - Cb - G - Bb
A#7b9 x - x - A# - D - Gb - B
B7b9 x - x - B - Db - A - C
Guitar versions of the chord
Notes in chord
C7b9 C - E - G - Bb - DbC#7b9 C# - F - Gb - D
D7b9 D - Fb - A - Eb
D#7b9 D# - G - Ab - E
E7b9 E - Gb - B - F
F7b9 F - A - C - Gb
F#7b9 F# - Ab - Cb - G
G7b9 G - B - D - Ab
G#7b9 G# - C - Db - A
A7b9 A - Cb - E - Bb
A#7b9 A# - D - F - B
B7b9 B - Db - Fb - C
The intervals are 1 – 3 – 5 – b7 - b9
Alternative movable shape with root on fifth string
An alternative fingering suitable for fingerpicking situations is this shape:
For example, C7-9 is played as X3X323 with this shape.
Chord progressions
Progressions including this chord type:
G13 - D7 - E7b9 - E7
Am7 - D7b9 - Gmaj9
C9 - C7b9 - F
E - C#9 - C#7b9 - F#m7 - B11
Chord comparisons
The flat nine chord has similarities with the dominant seventh and the dominant ninth:
Chord construction
C7 x - C - E - Bb - C - EC7b9 x - C - E - Bb - Db - x
C9 x - C - E - Bb - D - G
Guitar versions of the chord
Notes in chord
C7 C - E - G - BbC7b9 C - E - G - Bb - Db
C9 C - E - G - Bb - D
Theoretical order of notes
Note that C7, C9 and C7b9 are sometimes played without the fifth interval.
Illustrated comparison with charts including intervals:
C7 with C tone on 1st fret, 2nd string
C9 with D tone (9) on 3rd fret, 2nd string
C7b9 with Db tone (9b) on 2nd fret, 2nd string
The charts show how the 9th in the chord is flattened by moving it one step down.