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F1 · 43.65 Hz

F1 is piano key 9 of 88 and MIDI note 29 - the deep bass register, the territory of bass guitar low strings and organ pedals. Play the pure tone below, tune to it, or explore the note in every octave.

43.65Hz

Volume50%

Waveform

F1 at a glance

Frequency

43.65 Hz

Wavelength (in air)

7.86 m

MIDI note

29

Piano key

9 / 88

Octave

1

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 F1 is exactly 440 × 2^(-40/12) Hz. Under alternative references the note shifts with the reference: at A4 = 432 Hz, F1 becomes 42.86 Hz.

F in every octave

Note	Frequency	MIDI	Piano key
F1 ←	43.65 Hz	29	9
F2	87.31 Hz	41	21
F3	174.61 Hz	53	33
F4	349.23 Hz	65	45
F5	698.46 Hz	77	57
F6	1396.9 Hz	89	69
F7	2793.8 Hz	101	81

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

D♯1 · 38.89 Hz E1 · 41.20 HzF1 · 43.65 HzF♯1 · 46.25 Hz G1 · 49.00 Hz

One semitone down is E1 at 41.20 Hz; one semitone up is F♯1 at 46.25 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.

F1 FAQ

What frequency is F1?

F1 is 43.65 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 F1 sits 40 semitones below A4.

What MIDI number and piano key is F1?

F1 is MIDI note 29 and key 9 of 88 on a standard piano. Octave numbering follows scientific pitch notation, where middle C is C4 (MIDI 60).

How do I tune to F1?

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 39.2 cents off.

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