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B♭7 / A♯7: frequency and where to play it

3729.3 Hz

B♭7 in equal temperament at A4 = 440 Hz · MIDI note 106 · piano key 86 · Helmholtz a♯′×4

B♭73729.3 Hzat A4 = 440 Hz

B♭7 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.

ReferenceB♭7vs 440
A4 = 415 Hz · Baroque pitch3517.4 Hz−101.3¢
A4 = 432 Hz · “Verdi” pitch3661.5 Hz−31.8¢
A4 = 440 Hz · Standard (ISO 16)3729.3 Hz—
A4 = 442 Hz · Orchestral3746.3 Hz+7.9¢

One cycle of B♭7 lasts 268.1 µs, and its wavelength in air at 20 °C is 9.2 cm. Hold it as a steady tone in the tone generator.

B♭7 on the piano

B♭7 is key 86 of 88, counting from the bottom — the black key between A and B. Press any key below to compare it with its neighbours.

C2D2E2F2G2A2B2C3D3E3F3G3A3B3C4D4E4F4G4A4B4C5D5E5F5G5A5B5C6D6E6F6G6A6B6C7D7E7F7G7A7B7C8D8E8F8G8A8B8C♯2E♭2F♯2A♭2B♭2C♯3E♭3F♯3A♭3B♭3C♯4E♭4F♯4A♭4B♭4C♯5E♭5F♯5A♭5B♭5C♯6E♭6F♯6A♭6B♭6C♯7E♭7F♯7A♭7B♭7C♯8E♭8F♯8A♭8B♭8C2C3C4C5C6C7C8B♭7

B♭7 on the guitar

B♭7 is above the highest fret of any standard guitar, so a guitar in standard tuning cannot play it.

B♭7 on the staff

♭
Written an octave down, marked 8va

Instruments that can play B♭7

4 instruments play B♭7 within the normal range, and 1 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.

Woodwind

Tuned percussion

Keyboards and free reeds

Only at the extreme of their range

B♭7 is outside the typical range of all six voice types. Test your own range.

The harmonics of B♭7

A played B♭7 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.

HarmonicFrequencyNearest noteOff by
1 (fundamental)3729.3 HzB♭70¢
27458.6 HzB♭80¢
311,188 HzF9+2.0¢
414,917 HzB♭90¢
518,647 HzD10−13.7¢
622,376 HzF10+2.0¢
726,105 HzA♭10−31.2¢
829,834 HzB♭100¢

Frequently asked questions

What is the frequency of B♭7?

B♭7 is 3729.3 Hz in equal temperament with A4 tuned to 440 Hz, the international standard. At A4 = 432 Hz it is 3661.5 Hz, and at the orchestral A4 = 442 Hz it is 3746.3 Hz.

Is B♭7 the same note as A♯7?

On a piano, a guitar or a tuner, yes: B♭7 and A♯7 are the same key and the same frequency, 3729.3 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♭7 on a piano?

B♭7 is key 86 of 88, counting from the bottom — the black key between A and B.

Which instruments can play B♭7?

4 of the instruments we chart play B♭7 within their normal range, including piccolo, xylophone, glockenspiel, piano, and 1 more reach it only at the extreme of their range.

Typing it? B♭7 is also written Bb7 or A#7. Convert any frequency on the Hz-to-note converter.