G Seventh Flat Five Chord (G7♭5)

1Composition: what it contains

G – B – D♭ – F

Symbol

G7♭5

Also written

G7♭5, G7(♭5), G7-5

Formula

1 3 ♭5 ♭7

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

Used as an altered V7 in jazz, bebop and Latin jazz, and as a dominant built on the flat second in a tritone substitution (♭II7♭5–I), where its symmetrical tritones make it identical to the 7♭5 chord a tritone away. It also appears in French augmented-sixth harmony in classical music. The whole-tone scale, Lydian dominant (as ♯11) or the altered scale fits over it, depending on the other tensions. Because its two tritones are symmetrical, it sounds equally convincing from either root.

4Dosage: how to practise it

On guitar, learn the shapes rooted on the sixth string and fifth string, and notice that moving the shape six frets gives the same notes. On piano, play 1-3-♭5-♭7 in all inversions and practise ii7–V7♭5–Imaj7 and ii7–♭II7♭5–Imaj7 at 70–120 BPM. Arpeggiate 1-3-♭5-♭7. Five minutes daily, comparing with 7 and 7♯11. Improvise over it with the whole-tone scale and then with Lydian dominant. Practise tritone substitutions in all keys, playing the ♭5 shape and the substitute chord side by side so you hear that they are the same notes.

5Warnings and common mistakes

Do not confuse 7♭5 with m7♭5: the third is major here. Do not play the natural fifth together with the flat fifth. In a context with a natural fifth in the melody, write 7♯11 rather than 7♭5. Because of its symmetry, beginners mislabel its root; check the bass. The symbol '7-5' is ambiguous and can be misread; prefer 7♭5. On piano, avoid doubling the flat fifth.

6Interactions with chords, scales and keys

Inversions

• Inversion 1 · G7♭5/B · B – D♭ – F – G Play
• Inversion 2 · G7♭5/D♭ · D♭ – F – G – B Play
• Inversion 3 · G7♭5/F · F – G – B – D♭ Play

Scales to play over G7♭5

• G Whole Tone Scale
• G Half-Whole Diminished Scale
• G Lydian Dominant Scale
• G Altered Scale

7Other presentations available

The same chord from every note

C7♭5 C♯7♭5 D7♭5 E♭7♭5 E7♭5 F7♭5 F♯7♭5 A♭7♭5 A7♭5 B♭7♭5 B7♭5

Other chords on G

G Gm Gdim Gaug Gsus2 Gsus4 G5 G6 Gm6 G7 Gmaj7 Gm7 Gm7♭5 Gdim7 Gm(maj7) G7sus4 Gadd9 Gm(add9) G6/9 G9 Gmaj9 Gm9 G11 Gm11 G13 G7♭9 G7♯9 G7♯5