1. In music, the octave below the lowest note of a standard musical range or instrument; the register below the lowest octave.
Usage: music; technical

Examples

• The organ's contraoctave pipes produce the deepest, most resonant tones.
• Modern synthesizers can generate sounds in the contraoctave range.
• The contraoctave register is rarely used in standard orchestral writing.
• Bass instruments like the tuba can reach into the contraoctave.
• The composer specified notes in the contraoctave for dramatic effect.