D (D-flat) is a musical note lying a diatonic semitone above C and a chromatic semitone below D. It is thus enharmonic to C. In the French solfège it is known as re bémol. It is the second semitone of the solfège.
When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of middle D (or D4) is approximately 277.183 Hz.[1] See pitch (music) for a discussion of historical variations in frequency.
| Scientific designation | Helmholtz designation | Octave name | Frequency (Hz) | |
|---|---|---|---|---|
| D−1 | D͵͵͵ or ͵͵͵D or DDDD | Subsubcontra | ||
| D0 | D͵͵ or ͵͵D or DDD | Subcontra | ||
| D1 | D͵ or ͵D or DD | Contra | ||
| D2 | D | Great | ||
| D3 | d | Small | ||
| D4 | d | One-lined | ||
| D5 | d | Two-lined | ||
| D6 | d | Three-lined | ||
| D7 | d | Four-lined | ||
| D8 | d | Five-lined | ||
| D9 | d | Six-lined | ||
| D10 | d | Seven-lined |