tonal.fm
PRO

All tools offline & ad-free — $9 once

→

B2 · 123.47 Hz

B2 is piano key 27 of 88 and MIDI note 47 - the bass register, where bass lines and a male bass voice live. Play the pure tone below, tune to it, or explore the note in every octave.

123.47Hz
Volume50%
Waveform

B2 at a glance

Frequency
123.47 Hz
Wavelength (in air)
2.78 m
MIDI note
47
Piano key
27 / 88
Octave
2
Enharmonic
—

All values assume twelve-tone equal temperament at the international standard pitch of A4 = 440 Hz. In that system every semitone has the same size - a frequency ratio of 2^(1/12) - so B2 is exactly 440 × 2^(-22/12) Hz. Under alternative references the note shifts with the reference: at A4 = 432 Hz, B2 becomes 121.23 Hz.

B in every octave

NoteFrequencyMIDIPiano key
B030.87 Hz233
B161.74 Hz3515
B2 ←123.47 Hz4727
B3246.94 Hz5939
B4493.88 Hz7151
B5987.77 Hz8363
B61975.5 Hz9575
B73951.1 Hz10787

Each octave doubles the frequency - the simplest relationship in music, and the reason notes an octave apart sound like “the same note, higher”.

Neighboring notes

A2 · 110.00 HzA♯2 · 116.54 HzB2 · 123.47 HzC3 · 130.81 HzC♯3 · 138.59 Hz

One semitone down is A♯2 at 116.54 Hz; one semitone up is C3 at 130.81 Hz. Need a frequency between notes, or a different waveform? The tone generator plays anything from 20 Hz to 20 kHz; the note ↔ frequency converter does the math both directions, and the chromatic tuner listens to your instrument and shows the offset in cents.

B2 FAQ

What frequency is B2?

B2 is 123.47 Hz in twelve-tone equal temperament with the standard reference of A4 = 440 Hz. Every semitone step multiplies the frequency by the twelfth root of two (about 1.0595), and B2 sits 22 semitones below A4.

What MIDI number and piano key is B2?

B2 is MIDI note 47 and key 27 of 88 on a standard piano. Octave numbering follows scientific pitch notation, where middle C is C4 (MIDI 60).

How do I tune to B2?

Play the tone above and match your instrument by ear until the beating between the two pitches slows and disappears, or use the chromatic tuner with your microphone for a cents readout. Small mistunings show up as slow beats: one beat per second at this pitch means you are about 14.0 cents off.

Related Tools

Tone Generator

Single tones, 20 Hz - 20 kHz

Signal Generator

Test signals for engineers

Multi-Tone Generator

Several frequencies at once

Sweep Generator

Linear & exponential sweeps

Noise Generator

White, pink & brown noise

White Noise

Full-spectrum masking

Browse all tools →