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# C (musical note)

Middle C

C or Do is the first note of the C major scale, the third note of the A minor scale (the relative minor of C major), and the fourth note (G, A, B, C) of the Guidonian hand, commonly pitched around 261.63 Hz. The actual frequency has depended on historical pitch standards, and for transposing instruments a distinction is made between written and sounding or concert pitch.

In English the term Do is used interchangeably with C only by adherents of fixed-Do solfège; in the movable Do system Do refers to the tonic of the prevailing key.

## Frequency

Historically, concert pitch has varied. For an instrument in equal temperament tuned to the A440 pitch standard widely adopted in 1939, middle C has a frequency around 261.63 Hz (for other notes see piano key frequencies). 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. A movement to restore the older A435 standard has used the banners "Verdi tuning", "philosophical pitch" or the easily confused scientific pitch.

## Octave nomenclature

### Middle C

Middle C (the fourth C key from left on a standard 88-key piano keyboard) is designated C4 in scientific pitch notation, and c′ in Helmholtz pitch notation; it is note number 60 in MIDI notation.[1]

While the expression Middle C is generally clear across instruments and clefs, some musicians naturally use the term to refer to the C note in the middle of their specific instrument's range. C4 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 technically inaccurate practice has led some pedagogues to encourage standardizing on C4 as the definitive Middle C in instructional materials across all instruments.[2]

On the Grand Staff, middle-C is notated with a ledger line above the top line of the bass staff or below the bottom line of the treble staff. Alternatively, it is written on the centre line of a staff using the alto clef, or on the fourth line from the bottom, or the second line from the top, of staves using the tenor clef.

### Other octaves

In vocal music, the term High C (sometimes less ambiguously called Top C[3]) can refer to either the soprano's C6 (1046.502 Hz; c′′′ in Helmholtz notation) or the tenor's C5; both are written as the C two ledger lines above the treble clef but the tenor voice sings an octave lower. The term Low C is sometimes used in vocal music to refer to C2 because this is considered the divide between true basses and bass-baritones: a basso can sing this note easily, whereas other male voices, including bass-baritones, typically cannot.

Tenor C is an organ builder's term for small C or C3 (130.813 Hz), the note one octave below Middle C. In stoplists it usually means that a rank is not full compass, omitting the bottom octave.

## Designation by octave

Scientific designation Helmholtz designation Octave name Frequency (Hz) Other names Audio
C−1 C͵͵͵ or ͵͵͵C or CCCC Octocontra 8.176
C0 C͵͵ or ͵͵C or CCC Subcontra 16.352
C1 C͵ or ͵C or CC Contra 32.703
C2 C Great 65.406 Low C, cello C, 8' C (see organ pipe length)
C3 c Small 130.813 4' C or tenor C (organ), viola C
C4 c′ One-lined 261.626 Middle C
C5 c′′ Two-lined 523.251 Treble C, high C (written an octave higher for tenor voices)[4]
C6 c′′′ Three-lined 1046.502 High C (soprano)
C7 c′′′′ Four-lined 2093.005 Double high C[citation needed]
C8 c′′′′′ Five-lined 4186.009 Eighth octave C, triple high C
C9 c′′′′′′ Six-lined 8372.018 Quadruple high C
C10 c′′′′′′′ Seven-lined 16744.036 Quintuple high C

Note that for a classical piano and musical theory, the middle C is usually labelled as C4; However, in the MIDI standard definition (like the one used in Apple's GarageBand), this middle C (261.626 Hz) is labelled C3. In practice, a MIDI software can label middle C (261.626 Hz) as C3-C5, which can cause confusion, especially for beginners.

## Graphic presentation

Middle C in four clefs
Position of Middle C on a standard 88-key keyboard