A♯1 on the staff and the piano
On the bass clef, A♯1 sits on the third ledger line below the staff. The sharp sign raises A1 by one semitone. The same key can also be written B♭1, with a flat on the next line or space up.
On the piano, A♯1 is key 14 of 88, octave 1 - the black key between A1 and B1. It is 26 semitones below middle C (C4, key 40).
Play it on the online piano, or see all 88 note frequencies on one page.
A♯1 at a glance
All values assume twelve-tone equal temperament at the international standard pitch of A4 = 440 Hz. In that system every semitone has the same size - a frequency ratio of 2^(1/12) - so A♯1 is exactly 440 × 2^(-35/12) Hz. Under alternative references the note shifts with the reference: at A4 = 432 Hz, A♯1 becomes 57.21 Hz.
A♯ in every octave
| Note | Frequency | MIDI | Piano key |
|---|---|---|---|
| A♯0 | 29.14 Hz | 22 | 2 |
| A♯1 ← | 58.27 Hz | 34 | 14 |
| A♯2 | 116.54 Hz | 46 | 26 |
| A♯3 | 233.08 Hz | 58 | 38 |
| A♯4 | 466.16 Hz | 70 | 50 |
| A♯5 | 932.33 Hz | 82 | 62 |
| A♯6 | 1864.7 Hz | 94 | 74 |
| A♯7 | 3729.3 Hz | 106 | 86 |
Each octave doubles the frequency - the simplest relationship in music, and the reason notes an octave apart sound like “the same note, higher”.
Who plays A♯1
A♯1 is within the usual range of the piano, bass guitar and double bass. It is outside the usual range of all the classical voice types listed here.
- Piano: A0–C8
- Bass guitar (4-string): E1–G4
- Double bass: E1–G4
None of the usual voice ranges
Ranges are approximate: they are the commonly cited sounding (concert) pitches, and real ranges vary by player, instrument, tuning and repertoire. Guitar, bass guitar and double bass are written an octave higher than they sound; B♭ clarinet and trumpet are written a whole tone higher.
Neighboring notes
One semitone down is A1 at 55.00 Hz; one semitone up is B1 at 61.74 Hz. Need a frequency between notes, or a different waveform? The tone generator plays anything from 20 Hz to 20 kHz; the note ↔ frequency converter does the math both directions, and the chromatic tuner listens to your instrument and shows the offset in cents.