A (A-sharp; French: French: la dièse) is the eleventh semitone of the solfège.
This note lies a chromatic semitone above A and a diatonic semitone below B, thus being enharmonic to B (French: French: si bémol).
When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of the A above middle C is approximately 466.164Hz.[1] See pitch (music) for a discussion of historical variations in frequency.
| Scientific designation | Helmholtz designation | Octave name | Frequency (Hz) | |
|---|---|---|---|---|
| A−1 | A͵͵͵ or ͵͵͵A or AAAA | Subsubcontra | ||
| A0 | A͵͵ or ͵͵A or AAA | Subcontra | ||
| A1 | A͵ or ͵A or AA | Contra | ||
| A2 | A | Great | ||
| A3 | a | Small | ||
| A4 | a | One-lined | ||
| A5 | a | Two-lined | ||
| A6 | a | Three-lined | ||
| A7 | a | Four-lined | ||
| A8 | a | Five-lined | ||
| A9 | a | Six-lined | ||
| A10 | a | Seven-lined |