A♯-1 / B♭-1
14.568Hz at concert pitch
Press to hear a pure sine tone at this pitch.
MIDI note
10
Piano key
—
Octave
-1
Frequency
14.568 Hz
Period
68.6436 ms
Wavelength
23.5448 m
Pitch class
A♯
Notation
SPN
MIDI is the note number synths and software pass around (0–127). Pitch class is the note without its octave — all the A♯s share one. Enharmonic spellings (A♯-1 and B♭-1) name the same pitch two ways. This note falls outside the 88-key piano, so it has no piano key number.
At other reference pitches
| Reference (A4) | A♯-1 frequency | Where you meet it |
|---|---|---|
| 432 Hz | 14.303 Hz | the alternative-tuning circle |
| 440 Hzstandard | 14.568 Hz | the ISO 16 standard — concert pitch |
| 442 Hz | 14.634 Hz | many European orchestras tune a touch sharp |
| 443 Hz | 14.667 Hz | some sharper continental orchestras |
Every row is A♯-1 — only the A4 you tune to changes. A frequency scales straight with the reference: A♯-1 at 432 Hz is the 440 Hz value times 432⁄440.
Move around
Every A♯
Chords with A♯ in them
A♯ appears in each of these — see the whole chord grid.