A#1 — 58.270 Hz
A#1 (A-sharp 1) is 58.270 Hz in standard equal temperament at A=440 Hz. It is MIDI note number 34.
A#1 Frequency in All Tuning Systems
| Temperament | Frequency (Hz) | Cents from Equal | Common Usage |
|---|---|---|---|
| Equal Temperament | 58.270 Hz | 0.00 | Modern standard; piano, fretted instruments |
| Pythagorean | 57.942 Hz | -9.77 | Medieval/early music; string ensemble open fifths |
| Just Intonation (Major) | 58.866 Hz | +17.62 | A cappella vocal, barbershop, Renaissance |
| Just Intonation (Minor) | 58.866 Hz | +17.62 | Minor-key vocal music, string ensembles |
| Quarter-Comma Meantone | 58.849 Hz | +17.12 | Renaissance keyboard, early Baroque organ |
| Third-Comma Meantone | 59.032 Hz | +22.49 | Renaissance vocal music in minor keys |
| Sixth-Comma Meantone | 58.667 Hz | +11.76 | Baroque orchestral ensemble compromise |
| Werckmeister III | 58.667 Hz | +11.76 | Baroque keyboard; Bach contemporaries |
| Werckmeister IV | 58.601 Hz | +9.81 | Baroque keyboard, strong key contrast |
| Werckmeister V | 58.402 Hz | +3.92 | Specialized Baroque keyboard |
| Kirnberger III | 58.617 Hz | +10.28 | Classical-era keyboard, keys near C major |
| Vallotti | 58.468 Hz | +5.87 | Baroque/Classical orchestral tuning |
| Young (1799) | 58.534 Hz | +7.83 | Classical-era keyboard |
| Bach/Lehman | 58.468 Hz | +5.87 | Bach keyboard works, Well-Tempered Clavier |
| Neidhardt | 58.402 Hz | +3.92 | 18th century keyboard, near-equal alternative |
| Kellner (Bach) | 58.587 Hz | +9.39 | Bach keyboard reconstruction |
Positive cents = sharper than equal temperament. Negative cents = flatter. 100 cents = 1 semitone.
A#1 at Different Concert Pitches
The same note varies in frequency depending on the concert pitch standard used by your ensemble.
| Concert Pitch | Frequency (Hz) | Common Usage |
|---|---|---|
| A = 440 Hz (ISO standard) | 58.270 Hz | US, UK, and most modern ensembles worldwide |
| A = 442 Hz | 58.535 Hz | Many European orchestras; France, Germany |
| A = 443 Hz | 58.668 Hz | Berlin Philharmonic; some US orchestras |
| A = 432 Hz | 57.211 Hz | Alternative tuning; Baroque revival |
| A = 415 Hz (Baroque) | 54.960 Hz | Historically-informed Baroque performance |
f = f_at_A440 × (concert_pitch / 440)
Instruments That Play A#1
A#1 (58.270 Hz) falls within the comfortable playing range of 12 instruments.
A#1 and Bb1 — Enharmonic Equivalents
A#1 and Bb1 are enharmonic equivalents — they sound identical at 58.270 Hz but are written differently depending on the musical context.
A#1: A♯ appears in sharp key signatures and is the leading tone in B major. Common key signatures: B major, F♯ major, C♯ major.
Bb1: B♭ appears as the tonic of B♭ major and is one of the most common flat notes in Western music. Common key signatures: B♭ major, E♭ major, F major.
Enharmonic equivalents share the same frequency in equal temperament. In historical temperaments like Pythagorean or meantone, they may differ slightly.
Why A#1 Varies Across Tuning Systems
A#1 shows a maximum deviation of +22.49 cents in Third-Comma Meantone compared to equal temperament. This 22-cent difference is clearly audible to trained musicians and reflects how different tuning philosophies prioritize interval purity over equal distribution.
In Third-Comma Meantone, A#1 is tuned sharper than equal temperament to achieve purer intervals with nearby notes in the tuning system's favored keys.
7 of the 15 non-equal temperaments deviate by more than 10 cents for A#1, making this note one where tuning system choice has a meaningful impact on pitch.
A#1 Across All Tuning Systems
Explore how A#1 is tuned in each historical temperament system. Each tuning system gives A#1 a slightly different frequency, affecting the harmonic character of chords and melodies.
Tune A#1 with precision — Get Tunable.
Tunable supports 15+ tuning systems including equal temperament, Pythagorean, just intonation, and historical well-temperaments. See exact Hz values in real-time as you play.