Bach Suite V (CGDAb) Tuning
Tune your cello to Bach Suite V (CGDAb) — C2, G2, D3, Ab3
About Bach Suite V (CGDAb) Tuning
Bach's Suite No. 5 in C minor (BWV 1011) calls for scordatura tuning, with the A string lowered one semitone to Ab3 (207.65 Hz). This is the only one of Bach's six unaccompanied cello suites that requires an altered tuning, and scholars believe Bach specified it deliberately to darken the instrument's upper voice and enable chord voicings that would be impossible in standard tuning. The lowered string creates a more veiled, somber tonal palette that matches the suite's unusually austere and introspective character.
Scordatura — the practice of intentionally mistuning one or more strings — was a common technique in Baroque string music, used by composers from Biber to Vivaldi. By lowering the A string to Ab, Bach gained access to specific double stops and resonances in C minor that standard tuning cannot produce. The open Ab3 serves as the minor sixth of C, creating haunting open-string sonorities when played against the lower strings. The Prelude of the Fifth Suite, written in the style of a French overture, exploits these unique voicings extensively.
Playing the Fifth Suite in scordatura requires the cellist to mentally transpose all fingerings on the top string, since each position now sounds a semitone lower than expected. This cognitive adjustment is part of the suite's difficulty. Some modern cellists choose to play the suite in standard tuning and simply adjust their fingering, but this sacrifices the specific open-string resonances and chord voicings that Bach wrote into the score. Historically informed performers almost universally use the scordatura as Bach intended.
String Notes
Recommended Strings
Since only the A string is lowered by a semitone, standard string sets work well for this tuning. The slight reduction in tension on the A string is negligible and does not require a different gauge. Gut-core A strings, such as Pirastro Eudoxa or Pirastro Chorda, are a popular choice for historically informed performances of the Bach Suites, as they produce the warm, complex overtones characteristic of Baroque sound. If using steel-core strings, the fine tuner on the A string makes the small downward adjustment precise and easy to reverse.
How to Tune to Bach Suite V (CGDAb)
- 1.Start from standard CGDA tuning. Only the A string needs to change — the lower three strings remain at their standard pitches.
- 2.Lower the A string from A3 (220 Hz) down one semitone to Ab3 (207.65 Hz). Use a chromatic tuner for precision, as the difference between A and Ab is subtle.
- 3.Verify the interval between D3 and Ab3. It should be a diminished fifth (tritone), which will sound distinctly dissonant compared to the pure perfect fifth of standard tuning. This dissonance is intentional and characteristic of the scordatura.
- 4.Check the C-G and G-D fifths to confirm they remain pure. The lower three strings should be unaffected by the A string adjustment.
- 5.Play a few open-string chords to familiarize your ear with the altered resonances. The open Ab against the open C and G strings produces the dark C minor sonority that defines this suite's sound world.
Best Keys for Bach Suite V (CGDAb)
C Minor
The home key of Bach's Fifth Suite. The lowered A string (Ab) provides the minor sixth of C, enabling open-string voicings that reinforce the key's dark, grave character throughout the suite.
Eb Major
The relative major of C minor and a key frequently visited in the suite's dance movements. The open Ab serves as the fourth degree in Eb major, adding warmth to passages in this key.
G Minor
The dominant minor, used in transitional passages and sequences within the suite. The open G string provides a natural tonic drone for passages in this key.
F Minor
The subdominant minor, appearing in some of the suite's more chromatic episodes. The Ab string resonates as the minor third of F, supporting the harmonic texture.