Great octave
Octave range from C to B.
What it means
The great octave spans the pitch range from C to B and is written in capital letters in the German naming system. It lies one octave below the small octave, which is marked with lower-case letters, and two octaves below the one-line octave, which contains standard concert pitch a'. The great C has a frequency of about 65 hertz.
Musical use
The great octave belongs to the low register, in which for instance the double bass, bassoon, trombone, tuba, the low male voice, and the left hand at the piano play. In scientific notation it is called C2 to B2. Below lie the contra octave and the sub-contra octave, in which only few instruments play.
The great octave should be distinguished from the small octave, whose notes are named with lower-case letters, and from the one-line octave, marked by a raised 1. The naming by capital letters is a German tradition; in the English-speaking world the octave is usually given by numbers.
Performance practice
When you read notes in the great octave, watch the ledger lines below the staff in the bass clef and name the notes aloud at first. On instruments with a low register, such as double bass or trombone, intonation and response in this range need especially careful practice.