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About A♯2
A♯2 / B♭2 has a frequency of 116.54 Hz in standard tuning, where A4 is fixed at 440 Hz. It is MIDI note 46 and key number 26 on an 88-key piano.
In equal temperament every semitone multiplies the frequency by the twelfth root of two (≈1.05946), so A♯2 is 23 semitones below A4: f = 440 × 2^((46 − 69) / 12) = 116.54 Hz. The number in the name is the octave in scientific pitch notation, which starts each octave on C.
A♯2 and B♭2 are enharmonic: on a piano or in equal temperament they are the same key and the same frequency, but they are spelled differently depending on the key signature.
A♯2 frequency in different tunings
| Tuning reference | A♯2 frequency |
|---|---|
| A4 = 440 Hz (ISO 16 standard) | 116.54 Hz |
| A4 = 442 Hz (many European orchestras) | 117.07 Hz |
| A4 = 443 Hz (Berlin, Vienna) | 117.34 Hz |
| A4 = 435 Hz (French diapason normal, 1859) | 115.22 Hz |
| A4 = 432 Hz (alternative tuning) | 114.42 Hz |
| A4 = 415 Hz (Baroque pitch) | 109.92 Hz |
| C4 = 256 Hz (scientific pitch) | 114.04 Hz |
Where to play A♯2 on a guitar
Standard tuning (E A D G B E), frets 0–22.
- 6th string (low E), fret 6
- 5th string (A), fret 1
Intervals from A♯2
| Interval | Note | Frequency | Ratio (just) |
|---|---|---|---|
| Minor second | B2 | 123.47 Hz | 16:15 |
| Major second | C3 | 130.81 Hz | 9:8 |
| Minor third | C♯3 | 138.59 Hz | 6:5 |
| Major third | D3 | 146.83 Hz | 5:4 |
| Perfect fourth | D♯3 | 155.56 Hz | 4:3 |
| Tritone | E3 | 164.81 Hz | 45:32 |
| Perfect fifth | F3 | 174.61 Hz | 3:2 |
| Minor sixth | F♯3 | 185 Hz | 8:5 |
| Major sixth | G3 | 196 Hz | 5:3 |
| Minor seventh | G♯3 | 207.65 Hz | 9:5 |
| Major seventh | A3 | 220 Hz | 15:8 |
| Octave | A♯3 | 233.08 Hz | 2:1 |
Instruments and voices that can play A♯2
Frequently asked questions
What is the frequency of A♯2?
A♯2 is 116.54 Hz when A4 = 440 Hz (114.42 Hz if A4 = 432 Hz).
What MIDI number is A♯2?
A♯2 is MIDI note number 46.
Is A♯2 on a piano?
Yes – it is key 26 of 88.
Where is A♯2 on the guitar?
In standard tuning: 6th string (low E), fret 6; 5th string (A), fret 1.