A♯0 / B♭0
29.135Hz at concert pitch
Press to hear a pure sine tone at this pitch.
MIDI note
22
Piano key
2
Octave
0
Frequency
29.135 Hz
Period
34.323 ms
Wavelength
11.7728 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♯0 and B♭0) name the same pitch two ways.
At other reference pitches
| Reference (A4) | A♯0 frequency | Where you meet it |
|---|---|---|
| 432 Hz | 28.606 Hz | the alternative-tuning circle |
| 440 Hzstandard | 29.135 Hz | the ISO 16 standard — concert pitch |
| 442 Hz | 29.268 Hz | many European orchestras tune a touch sharp |
| 443 Hz | 29.334 Hz | some sharper continental orchestras |
Every row is A♯0 — only the A4 you tune to changes. A frequency scales straight with the reference: A♯0 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.