B♭1 at every common reference pitch
A note’s frequency depends on what A4 is tuned to. The standard is 440 Hz; the other three are the ones you are most likely to meet. The cents column is how far each one sits from the 440 version — the same for every note, because changing the reference moves the whole scale together.
| Reference | B♭1 | vs 440 |
|---|---|---|
| A4 = 415 Hz · Baroque pitch | 54.96 Hz | −101.3¢ |
| A4 = 432 Hz · “Verdi” pitch | 57.21 Hz | −31.8¢ |
| A4 = 440 Hz · Standard (ISO 16) | 58.27 Hz | — |
| A4 = 442 Hz · Orchestral | 58.54 Hz | +7.9¢ |
One cycle of B♭1 lasts 17.161 ms, and its wavelength in air at 20 °C is 5.89 m. Hold it as a steady tone in the tone generator.
B♭1 on the piano
B♭1 is key 14 of 88, counting from the bottom — the black key between A and B. Press any key below to compare it with its neighbours.
B♭1 on the guitar
B♭1 is below the guitar’s lowest note, the open low E (E2), so a guitar in standard tuning cannot play it.
B♭1 on the staff
Instruments that can play B♭1
9 instruments play B♭1 within the normal range, and 2 reach it only at the extreme of theirs. Each links to its range chart; for a transposing instrument, the note on its part is shown.
Bowed strings
Keyboards and free reeds
Only at the extreme of their range
B♭1 is outside the typical range of all six voice types. Test your own range.
The harmonics of B♭1
A played B♭1 is not one frequency. A string or a pipe also sounds whole-number multiples of it, and the mix of those harmonics is the instrument’s tone. Here is where the first eight land — and why the 7th sounds out of tune against a piano.
| Harmonic | Frequency | Nearest note | Off by |
|---|---|---|---|
| 1 (fundamental) | 58.27 Hz | B♭1 | 0¢ |
| 2 | 116.54 Hz | B♭2 | 0¢ |
| 3 | 174.81 Hz | F3 | +2.0¢ |
| 4 | 233.08 Hz | B♭3 | 0¢ |
| 5 | 291.35 Hz | D4 | −13.7¢ |
| 6 | 349.62 Hz | F4 | +2.0¢ |
| 7 | 407.89 Hz | A♭4 | −31.2¢ |
| 8 | 466.16 Hz | B♭4 | 0¢ |
Frequently asked questions
What is the frequency of B♭1?
B♭1 is 58.27 Hz in equal temperament with A4 tuned to 440 Hz, the international standard. At A4 = 432 Hz it is 57.21 Hz, and at the orchestral A4 = 442 Hz it is 58.54 Hz.
Is B♭1 the same note as A♯1?
On a piano, a guitar or a tuner, yes: B♭1 and A♯1 are the same key and the same frequency, 58.27 Hz, in equal temperament. They are two names for one pitch (enharmonic equivalents). Which one is written depends on the key — sharps in sharp keys, flats in flat keys — and a string or wind player may pitch them a few cents apart when playing in just intonation.
How do I play B♭1 on a piano?
B♭1 is key 14 of 88, counting from the bottom — the black key between A and B.
Which instruments can play B♭1?
9 of the instruments we chart play B♭1 within their normal range, including double bass, 8-string guitar, bass guitar, bass ukulele, bassoon, and 2 more reach it only at the extreme of their range.
Typing it? B♭1 is also written Bb1 or A#1. Convert any frequency on the Hz-to-note converter.