How to Tune to Open C
- Start from standard tuning. The G and high E strings stay where they are.
- Lower the low E string two whole steps (400 cents), to C2.
- Lower the A string a whole step, to G2.
- Lower the D string a whole step, to C3.
- Raise the B string a half step, to C4.
- Strum the open strings. You should hear a C major chord.
String Tension
The low string drops 400 cents and loses about 37% of its tension, so on light strings it can flap and buzz. Many players fit a heavier low string, around .056, for this tuning. The B string goes up only a half step, which adds little tension.
What Open C Is Used For
Open C has a wide, low sound, with the note C on three strings. It is used for slide guitar, fingerstyle acoustic, and folk music with droning open strings. Chords are barre shapes: one finger or a slide straight across the 5th fret plays F, and across the 7th fret G.
Tune up to each note rather than down to it. If you go past, loosen the string below the note and come back up: the string holds its pitch better that way.
String Notes and Frequencies
At the standard reference pitch, A4 = 440 Hz. String 1 is the highest-pitched string.
| String | Note | Frequency |
|---|---|---|
| 6 | C2 | 65.41 Hz |
| 5 | G2 | 98.00 Hz |
| 4 | C3 | 130.81 Hz |
| 3 | G3 | 196.00 Hz |
| 2 | C4 | 261.63 Hz |
| 1 | E4 | 329.63 Hz |