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C♯ 7th chord on bass (C♯7)
Also called or written C♯7, C♯, C♯ Dominant 7th or C♯ Major Minor 7th
C♯ 7th is built from C♯, E♯, G♯, and B. The 9th-fret shape stretches the pinky to fret 11 on the A string, making clean fretting the main challenge.
How it is built
Formula 1, 3, 5, ♭7
How do you play a C♯ 7th chord on bass?
C♯ 7th is played at the 9th fret as 9 11 9 10: index finger on the E string at fret 9, pinky finger on the A string at fret 11, middle finger on the D string at fret 9 and ring finger on the G string at fret 10.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 9 | 1 | C♯ (1) |
| 3 (A) | 11 | 4 | G♯ (5) |
| 2 (D) | 9 | 2 | B (♭7) |
| 1 (G) | 10 | 3 | E♯ (3) |
AdvancedThe pinky must reach from the 9th fret to the 11th fret on the A string while the other fingers hold their frets cleanly.
C♯7/G♯ inversion
C♯ 7th is played at the 3rd fret as 4 4 3 4: middle finger on the E string at fret 4, ring finger on the A string at fret 4, index finger on the D string at fret 3 and pinky finger on the G string at fret 4.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 4 | 2 | G♯ (5) |
| 3 (A) | 4 | 3 | C♯ (1) |
| 2 (D) | 3 | 1 | E♯ (3) |
| 1 (G) | 4 | 4 | B (♭7) |
C♯7/B inversion
C♯ 7th is played at the 6th fret as 7 8 6 6: ring finger on the E string at fret 7, pinky finger on the A string at fret 8, index finger on the D string at fret 6 and middle finger on the G string at fret 6.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 7 | 3 | B (♭7) |
| 3 (A) | 8 | 4 | E♯ (3) |
| 2 (D) | 6 | 1 | G♯ (5) |
| 1 (G) | 6 | 2 | C♯ (1) |
Why it sounds like that
C♯ 7th uses the formula 1, 3, 5, ♭7. The minor 7th interval between C♯ and B gives the chord its dominant quality, and the diminished 5th between E♯ and B adds tension. Compare it with C♯ major, which omits the ♭7.
What goes wrong with C♯ 7th?
- Letting the pinky collapse and buzz the A string at fret 11.
- Allowing the ring finger to touch the D string and mute it.
- Striking the open E string instead of fretting it at the 9th fret.
When to use it
C♯ 7th is the V chord in F♯ major, so it appears in progressions like F♯–B–C♯–F♯ (I–IV–V–I). Its dominant pull suits blues, rock, and funk bass lines that resolve to F♯.
Changing to and from C♯ 7th
- Move to F♯ major by lifting the pinky and shifting the index and middle fingers down one string each.
- Slide the shape down two frets to the 7th fret to play B 7th.
Which voicing to use
The 9th-fret shape has C♯ in the bass and is the most direct voicing. The C♯7/G♯ inversion at the 4th fret puts G♯ in the bass for a smoother transition from F♯ major, while the C♯7/B inversion at the 7th fret leads into F♯ major by step.
Other C♯ chords
Common questions
How is C♯ 7th written?
C♯ 7th is written as C♯7, or C#7 in ASCII. It is also spelled D♭ in enharmonic notation for the same sounding root.
How does C♯ 7th differ from C♯ major?
C♯ 7th adds a B note, the minor 7th, to the C♯ major triad. That B creates a tritone with E♯, giving C♯ 7th its dominant tension.
Why is C♯ 7th called a dominant 7th chord?
C♯ 7th is built on the fifth degree of F♯ major, where it functions as the dominant. The name comes from that dominant function, not from the chord's internal intervals.