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About A♯6
A♯6 / B♭6 has a frequency of 1.865 kHz in standard tuning, where A4 is fixed at 440 Hz. It is MIDI note 94 and key number 74 on an 88-key piano.
In equal temperament every semitone multiplies the frequency by the twelfth root of two (≈1.05946), so A♯6 is 25 semitones above A4: f = 440 × 2^((94 − 69) / 12) = 1,864.66 Hz. The number in the name is the octave in scientific pitch notation, which starts each octave on C.
A♯6 and B♭6 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♯6 frequency in different tunings
| Tuning reference | A♯6 frequency |
|---|---|
| A4 = 440 Hz (ISO 16 standard) | 1.865 kHz |
| A4 = 442 Hz (many European orchestras) | 1.873 kHz |
| A4 = 443 Hz (Berlin, Vienna) | 1.877 kHz |
| A4 = 435 Hz (French diapason normal, 1859) | 1.843 kHz |
| A4 = 432 Hz (alternative tuning) | 1.831 kHz |
| A4 = 415 Hz (Baroque pitch) | 1.759 kHz |
| C4 = 256 Hz (scientific pitch) | 1.825 kHz |
Intervals from A♯6
| Interval | Note | Frequency | Ratio (just) |
|---|---|---|---|
| Minor second | B6 | 1.976 kHz | 16:15 |
| Major second | C7 | 2.093 kHz | 9:8 |
| Minor third | C♯7 | 2.217 kHz | 6:5 |
| Major third | D7 | 2.349 kHz | 5:4 |
| Perfect fourth | D♯7 | 2.489 kHz | 4:3 |
| Tritone | E7 | 2.637 kHz | 45:32 |
| Perfect fifth | F7 | 2.794 kHz | 3:2 |
| Minor sixth | F♯7 | 2.96 kHz | 8:5 |
| Major sixth | G7 | 3.136 kHz | 5:3 |
| Minor seventh | G♯7 | 3.322 kHz | 9:5 |
| Major seventh | A7 | 3.52 kHz | 15:8 |
| Octave | A♯7 | 3.729 kHz | 2:1 |
Instruments and voices that can play A♯6
Frequently asked questions
What is the frequency of A♯6?
A♯6 is 1.865 kHz when A4 = 440 Hz (1.831 kHz if A4 = 432 Hz).
What MIDI number is A♯6?
A♯6 is MIDI note number 94.
Is A♯6 on a piano?
Yes – it is key 74 of 88.