Under the Helmholtz Octave Designation System, a name applied to the octave which extends from C

This octave can also be designated with three uppercase letters (i.e. CCC) or in the fundamental octave under Acoustical Society of America system (i.e. C_{0}). The MIDI Octave Designation System has two versions, one where note 1 (8.176 Hz) is octave "0" making the **Sub-contra** octave the first octave (i.e. C1), and the other with note 1 (8.176 Hz) at octave "-2" making the **Sub-contra** octave the negative 1 octave (i.e. C-1).

The indications 8vb and 15mb (shown below) can be used to represent the same pitches without as many ledger lines. The indication 15mb is rarely used today.

## Play Sub-contra Octave Example (MIDI file format) |

More about octave designations - More about pitch