G7b9 guitar chord
Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About G7b9 — shell voicings
G7b9 is G, B, D, F and Ab — G9 with the ninth lowered a semitone.
It sounds dark and urgent. The flat ninth comes from the harmonic minor, so this is the V of a minor key rather than a major one.
G7b9 notes and formula
| G | B | D | F | Ab |
|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | ♭9 |
Altered dominant — it points at a minor chord.
Also written G7(b9), G7-9 or G7♭9. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play G7b9
Root, third and seventh. The third and seventh, the guide tones, are what make the chord major, minor or dominant, so the fifth can go: it says nothing the symbol needs.
Three notes means a spare string, which is the real point. Put a tension on it.
G7b9 has 4 of them, on the bottom four strings, the top four strings and the middle four strings, from open position up to the 13th — all in one inversion, so the bass note never moves. The one to learn first is the G shape at the nut, which is the easiest grip here.
Start with 3231xx — no barre and down at the nut. 1 of the 6 shapes here sits in open position. 2 of the 6 need a barre. Together they cover the neck from the 1st fret to the 10th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 320131 | open position | G, root position | F | 1 open string |
| 3231xx | 1st fret | G, root position | Ab | all fretted |
| xx3434 | 3rd fret | F, 3rd inversion | Ab | all fretted |
| 353434 | 3rd fret | G, root position | Ab | barred |
| xx5464 | 4th fret | G, root position | Ab | all fretted |
| x-10-9-10-9-10 | 9th fret | G, root position | D | barred |
The same notes rebuilt from scratch give 14 drop 2, 9 drop 3, 15 rootless and 3 open string voicings, each on its own page.
Tensions. A shell of G7b9, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (C#), the b13 (Eb) and the 13 (E).
How to use G7b9
G7b9 is a dominant with its tension raised, so it still points at C — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.
Voice by voice, G7b9 → Cm. 3 voices move by a semitone, and one note is common to both chords.
| In G7b9 | Moves | In Cm |
|---|---|---|
| G, the root | stays where it is | G, the fifth |
| B, the major third | rises a semitone | C, the root |
| D, the fifth | rises a semitone | Eb, the minor third |
| F, the flat seventh | falls a whole tone | Eb, the minor third |
| Ab, the flat ninth | falls a semitone | G, the fifth |
What to play over G7b9
Every note of G7b9 is in G half-whole diminished.
Chords near G7b9
Change one note of G7b9 and you have G7 (drop the flat ninth), Galt (the fifth becomes a sharp fifth), G9 (the flat ninth becomes a ninth), G7#9 (the flat ninth becomes a minor third) or G/F (drop the flat ninth).
G7b9 is an altered chord — a dominant seventh with its fifth or ninth moved. Altered dominant chords on every root.
On G7b9’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.