Open C (CGCG) Tuning
Tune your cello to Open C (CGCG) — C2, G2, C3, G3
About Open C (CGCG) Tuning
Open C tuning (C2-G2-C3-G3) restrings the cello's intervallic structure by replacing the standard D3 and A3 strings with C3 and G3, creating two pairs of octave-related strings. When all four strings are played open, the result is a resonant C5 power chord — a bare fifth with no third, producing a stark, open sonority. This tuning has become a staple of contemporary and experimental cello music, favored by composers and improvisers who want to exploit the instrument's capacity for sustained drones, overtone-rich textures, and minimalist harmonic landscapes.
The paired octaves in Open C create extraordinarily powerful sympathetic resonance. When the lower C2 is bowed, the upper C3 vibrates in sympathy, and the two G strings reinforce each other similarly. This acoustic coupling produces a sound that is larger and more harmonically dense than what four differently-tuned strings can achieve. Composers like Terry Riley, whose work for cello has been championed by cellist Joan Jeanrenaud, have written extensively for this and similar open tunings, using the drone-like quality to build hypnotic, slowly evolving sound worlds.
For the cellist, Open C requires a fundamental rethinking of the fingerboard. Standard scale and arpeggio patterns no longer apply, since the intervals between strings alternate between fifths (C-G) and fourths (G-C). New fingering patterns must be developed, and the cellist gains access to parallel motion across strings that standard tuning does not easily permit. Double stops and chords take on new shapes, and the tuning rewards exploration and improvisation.
String Notes
Recommended Strings
Open C tuning requires two C strings and two G strings, which means you cannot simply use a standard four-string set. The lower C2 can use a standard cello C string. The G2 uses a standard G string. For the upper C3, a standard D string tuned down from D3 to C3 may work but will feel slightly loose — a slightly heavier gauge D string or a dedicated C3 string is preferable. The upper G3 uses a standard A string tuned down from A3 to G3, which also reduces tension. Experiment with gauges to find a balanced feel across all four strings.
How to Tune to Open C (CGCG)
- 1.Start from standard CGDA tuning. The C2 and G2 strings remain unchanged. Only the upper two strings need adjustment.
- 2.Lower the D string from D3 (146.83 Hz) down to C3 (130.81 Hz). This is a whole step drop. The C3 should sound exactly one octave above the open C2 string.
- 3.Lower the A string from A3 (220 Hz) down to G3 (196 Hz). This is a whole step drop. The G3 should sound exactly one octave above the open G2 string.
- 4.Verify the octave pairs: C2 and C3 should produce a clean, beatless octave, as should G2 and G3. Any wavering indicates one string in the pair is not quite in tune.
- 5.Play all four strings open. You should hear a powerful, open C5 chord (C and G only, no third). The paired octaves will create a noticeably fuller, more resonant sound than standard tuning.
Best Keys for Open C (CGCG)
C Major
The natural home key. Open strings provide the tonic and dominant, creating a powerful foundation for drones, ostinatos, and melodic improvisation in C major.
C Minor
Easily achieved by fingering Eb on the C strings. The open G strings serve as the dominant, and the lack of a fixed third in the open tuning makes the shift between major and minor fluid.
G Major
The dominant key. The open G strings provide the tonic while the C strings supply the subdominant, creating natural harmonic motion between G and C.
F Major
Accessible through first-position fingering. The open C strings serve as the dominant of F, and the tuning's resonance supports the key's warm character.