OPEN C
CGCEGC
A deep open-C tuning with repeated roots and fifths: broad low-end resonance, simple shapes, and enough space for upper-string melody.
CHANGE VALUES ARE SEMITONES FROM STANDARD TUNING. TUNE DOWN GRADUALLY.
The weight of open C
CGCEGC is open C major: root, fifth, octave, major third, fifth, octave. Compared with standard tuning, the entire guitar settles lower. The repeated C and G tones create a wide foundation while the upper strings remain available for melody.
From standard tuning
Starting from E A D G B E, lower every string: E to C, A to G, D to C, G to E, B to G, and high E to C. Tune in stages and check the neck feel. The guitar may need heavier strings if you plan to stay here.
First exercise
Begin with the middle four strings rather than the full open chord. Add the low C only when you want the arrangement to widen. The restraint makes the low note feel intentional instead of constant.
Keep in mind
Very low tunings expose setup differences quickly. If notes rattle or drift sharp under the finger, the instrument may be asking for a different string gauge or a small adjustment.