C-sharp (musical note)

${ \new Staff \with{ \magnifyStaff #3/2 } << \time 3/1 \override Score.TimeSignature #'stencil = ##f { \clef bass \cadenzaOn cis1_C-sharp \clef treble cis' cis'' } >> }$

C♯ (C-sharp) is a musical note lying a chromatic semitone above C and a diatonic semitone below D; it is the second semitone of the solfège. C-sharp is thus enharmonic to D♭. It is the second semitone in the French solfège and is known there as do dièse. In some European notations, it is known as Cis. In equal temperament it is also enharmonic with B (B-double sharp/Hisis).

When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of C♯₄ (the C♯ above middle C) is about 277.183 Hz. See pitch (music) for a discussion of historical variations in frequency.

Frequency

Historically, concert pitch has varied. For an instrument in equal temperament tuned to the A440 pitch standard widely adopted in 1939, middle C#, the note above middle C has a frequency around 277.18 Hz.^[1] 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, making the pitch of C# 276.8067 Hz. 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.

Designation by octave

Scientific designation	Helmholtz designation	Octave name	Frequency (Hz)	MIDI note number
C♯₋₁	C♯͵͵͵ or ͵͵͵C♯ or CCCC♯	Subsubcontra	8.662	1
C♯₀	C♯͵͵ or ͵͵C♯ or CCC♯	Subcontra	17.324	13
C♯₁	C♯͵ or ͵C♯ or CC♯	Contra	34.648	25
C♯₂	C♯	Great	69.296	37
C♯₃	c♯	Small	138.591	49
C♯₄	c♯′	One-lined	277.183	61
C♯₅	c♯′′	Two-lined	554.365	73
C♯₆	c♯′′′	Three-lined	1108.731	85
C♯₇	c♯′′′′	Four-lined	2217.461	97
C♯₈	c♯′′′′′	Five-lined	4434.922	109
C♯₉	c♯′′′′′′	Six-lined	8869.844	121
C♯₁₀	c♯′′′′′′′	Seven-lined	17739.688	N/A

Notation

Middle C♯ (C♯4) on the treble, alto, tenor and bass clefs, respectively.

Scales

Common scales beginning on C♯

C♯ major: C♯ D♯ E♯ F♯ G♯ A♯ B♯ C♯
C♯ natural minor: C♯ D♯ E F♯ G♯ A B C♯
C♯ harmonic minor: C♯ D♯ E F♯ G♯ A B♯ C♯
C♯ melodic minor ascending: C♯ D♯ E F♯ G♯ A♯ B♯ C♯
C♯ melodic minor descending: C♯ B A G♯ F♯ E D♯ C♯

Diatonic scales

C♯ Ionian: C♯ D♯ E♯ F♯ G♯ A♯ B♯ C♯
C♯ Dorian: C♯ D♯ E F♯ G♯ A♯ B C♯
C♯ Phrygian: C♯ D E F♯ G♯ A B C♯
C♯ Lydian: C♯ D♯ E♯ F G♯ A♯ B♯ C♯
C♯ Mixolydian: C♯ D♯ E♯ F♯ G♯ A♯ B C♯
C♯ Aeolian: C♯ D♯ E F♯ G♯ A B C♯
C♯ Locrian: C♯ D E F♯ G A B C♯

Jazz melodic minor

C♯ ascending melodic minor: C♯ D♯ E F♯ G♯ A♯ B♯ C♯
C♯ Dorian ♭2: C♯ D E F♯ G♯ A♯ B C♯
C♯ Lydian augmented: C♯ D♯ E♯ F G A♯ B♯ C♯
C♯ Lydian dominant: C♯ D♯ E♯ F G♯ A♯ B C♯
C♯ Mixolydian ♭6: C♯ D♯ E♯ F♯ G♯ A B C♯
C♯ Locrian ♮2: C♯ D♯ E F♯ G A B C♯
C♯ Altered: C♯ D E F G A B C♯

References

^ Suits, B. H. (1998). "Physics of Music Notes - Scales: Just vs Equal Temperament". MTU.edu. Michigan Technological University. Retrieved 5 February 2024.