C (musical note)

It has enharmonic equivalents of B♯ and D. In English the term Do is used interchangeably with C only in the context of fixed Do solfège; in the movable Do system Do refers to the tonic of the prevailing key.

Scientific pitch was originally proposed in 1713 by French physicist Joseph Sauveur and based on the numerically convenient frequency of 256 Hz for middle C, all C's being powers of two.

After the A440 pitch standard was adopted by musicians, the Acoustical Society of America published new frequency tables for scientific use.

C4 (approximately 261.626 Hz[3]) may be called Low C by someone playing a Western concert flute, which has a higher and narrower playing range than the piano, while C5 (523.251 Hz) would be middle C. This practice has led some to encourage standardizing on C4 as the definitive middle C in instructional materials across all instruments.

In vocal music, the term High C (sometimes called Top C[5]) can refer to either the soprano's C6 (1046.502 Hz; c′′′ in Helmholtz notation) or the tenor's C5; soprano written as the C two ledger lines above the treble clef, with the tenor voice the space above concert A, sung an octave lower.