Helmholtz Pitch Notation

How pitches at different octaves are written. Note that notes below the bass octave are also written CC instead of C,, etc.

Helmholtz pitch notation is a method of writing pitches using capital- or lower-case letters and prime symbols to represent octaves. A modified version of Helmholtz notation is found in the letter notation of Old and New German Tablature Notation.

See Also

Helmholtz pitch notation on english Wikipedia