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F♯ 7th flat 5 chord on guitar (F♯7♭5)
Also called or written F♯7♭5, F♯, F♯ Dominant 7th Flat 5 or F♯ 7th ♭5
F♯ 7th flat 5 is built from F♯, A♯, C, and E. The 1st-fret voicing uses a partial barre across the A and B strings, adding a physical challenge.
How it is built
Formula 1, 3, ♭5, ♭7
- Root positionF♯–A♯–C–EF♯7♭52-1-2-3-1-×
- First inversionA♯–C–E–F♯F♯7♭5/A♯×-1-2-3-1-2
- Second inversionC–E–F♯–A♯F♯7♭5/C×-3-4-3-5-×
- Third inversionE–F♯–A♯–CF♯7♭5/E×-×-2-3-1-2
How do you play an F♯ 7th flat 5 chord on guitar?
F♯ 7th flat 5 is played at the 1st fret as 2 1 2 3 1 ×: barre your index finger across fret 1, middle finger on the low E string at fret 2, ring finger on the D string at fret 2 and pinky finger on the G string at fret 3. The high e string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 2 | 2 | F♯ (1) |
| 5 (A) | 1 | 1 (barre) | A♯ (3) |
| 4 (D) | 2 | 3 | E (♭7) |
| 3 (G) | 3 | 4 | A♯ (3) |
| 2 (B) | 1 | 1 (barre) | C (♭5) |
| 1 (e) | muted | — | — |
AdvancedThe 1st-fret voicing requires a partial barre across the A and B strings while fretting the low E, D, and G strings cleanly.
2nd fret
F♯ 7th flat 5 is played at the 2nd fret as 2 3 2 3 × ×: index finger on the low E string at fret 2, ring finger on the A string at fret 3, middle finger on the D string at fret 2 and pinky finger on the G string at fret 3. The B and high e strings stay muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 2 | 1 | F♯ (1) |
| 5 (A) | 3 | 3 | C (♭5) |
| 4 (D) | 2 | 2 | E (♭7) |
| 3 (G) | 3 | 4 | A♯ (3) |
| 2 (B) | muted | — | — |
| 1 (e) | muted | — | — |
4th fret
F♯ 7th flat 5 is played at the 4th fret as × × 4 5 5 6: index finger on the D string at fret 4, middle finger on the G string at fret 5, ring finger on the B string at fret 5 and pinky finger on the high e string at fret 6. The low E and A strings stay muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | muted | — | — |
| 4 (D) | 4 | 1 | F♯ (1) |
| 3 (G) | 5 | 2 | C (♭5) |
| 2 (B) | 5 | 3 | E (♭7) |
| 1 (e) | 6 | 4 | A♯ (3) |
9th fret
F♯ 7th flat 5 is played at the 9th fret as × 9 10 9 11 ×: index finger on the A string at fret 9, ring finger on the D string at fret 10, middle finger on the G string at fret 9 and pinky finger on the B string at fret 11. The low E and high e strings stay muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | 9 | 1 | F♯ (1) |
| 4 (D) | 10 | 3 | C (♭5) |
| 3 (G) | 9 | 2 | E (♭7) |
| 2 (B) | 11 | 4 | A♯ (3) |
| 1 (e) | muted | — | — |
13th fret
F♯ 7th flat 5 is played at the 13th fret as 14 13 14 15 13 ×: barre your index finger across fret 13, middle finger on the low E string at fret 14, ring finger on the D string at fret 14 and pinky finger on the G string at fret 15. The high e string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 14 | 2 | F♯ (1) |
| 5 (A) | 13 | 1 (barre) | A♯ (3) |
| 4 (D) | 14 | 3 | E (♭7) |
| 3 (G) | 15 | 4 | A♯ (3) |
| 2 (B) | 13 | 1 (barre) | C (♭5) |
| 1 (e) | muted | — | — |
Why it sounds like that
F♯ 7th flat 5 combines a major 3rd, a diminished 5th, and a minor 7th. The diminished 5th between F♯ and C creates the chord's tension. Compare it to F♯ 7th, which uses C♯ instead of C.
What goes wrong with F♯ 7th flat 5?
- Not pressing the barre hard enough, causing the B string to buzz.
- Letting the high E string ring out and add an unwanted E note.
- Flattening the pinky and muting the G string.
When to use it
F♯ 7th flat 5 functions as a dominant chord in B major, resolving to B major. Its dissonance suits jazz and fusion. Use it before B major or F♯ 7th.
Changing to and from F♯ 7th flat 5
- From the 1st-fret shape, move your index finger to the 2nd fret of the A string and your middle finger to the 3rd fret of the low E string for G 7th flat 5.
- Slide the 1st-fret shape up two frets to the 3rd fret to get A♭ 7th flat 5.
Which voicing to use
The 1st-fret voicing is the most accessible, but the 13th-fret barre version offers a fuller sound with the root on the low E. The 4th-fret shape places the root on the D string for a brighter register.
Other F♯ chords
Common questions
How is F♯ 7th flat 5 written?
F♯ 7th flat 5 appears as F♯7♭5 or F♯. The ASCII root is F#. It is also spelled G♭ in enharmonic notation for the same sounding root.
What is the difference between F♯ 7th flat 5 and F♯ 7th?
F♯ 7th flat 5 lowers the perfect 5th of F♯ 7th by one semitone to C. That creates a diminished 5th interval and a more dissonant sound.
Why does F♯ 7th flat 5 sound so unstable?
F♯ 7th flat 5 contains a tritone between F♯ and C, which creates strong tension. The chord wants to resolve, typically to B major.