[{"data":1,"prerenderedAt":27},["ShallowReactive",2],{"content-note-frequency-en":3},{"about":4,"steps":7,"faq":11},[5,6],"Every note has a frequency: the concert pitch A4 usually vibrates at 440 Hz, and one octave up the frequency doubles. In equal temperament every semitone is higher by a factor of the 12th root of 2 (about 1.0595). This converter turns note names into frequencies and finds the nearest note of a measured frequency, including the deviation in cents.","For every note it shows the MIDI number, the name in Helmholtz notation (c′, a′), the period and the wavelength in air. You can change the concert pitch, e.g. to 443 Hz used by many orchestras or to 432 Hz. A switch shows international (B, Bb, F#, Eb) or German note names (H, B, Fis, Es). You can listen to the tone right in your browser; for chords, use the [[chord-finder]].",[8,9,10],"Choose whether to convert a note to hertz or a frequency to a note – or show a whole octave as a table.","Enter the note with octave (e.g. A4 or C#3), click a key on the keyboard or enter the frequency in Hz.","Adjust the concert pitch if needed and read the frequency, deviation in cents, MIDI number and wavelength.",[12,15,18,21,24],{"q":13,"a":14},"How do you calculate the frequency of a note?","In equal temperament, f = 440 Hz × 2^((n − 69) ÷ 12), where n is the MIDI number (A4 = 69, C4 = 60). Middle C therefore has about 261.63 Hz.",{"q":16,"a":17},"What is a cent?","A cent is one hundredth of a semitone. Most people cannot hear deviations below about 5 cents. 445 Hz, for example, is about 20 cents above A4 at 440 Hz.",{"q":19,"a":20},"Which octave numbering does the converter use?","Scientific pitch notation: C4 is middle C on the piano and A4 the A above it. The Helmholtz name with primes (c, c′, c′′) and subscripts for the low octaves (C₁) is shown as well. Some manufacturers call middle C “C3” – then every octave is one lower.",{"q":22,"a":23},"Why is B called H in German?","In German notation the note between A and C is called “H”, and “B” is the note a semitone lower (Bb internationally). Sharps get the suffix -is (Fis = F#), flats -es (Des, Es, As). With “German (H)” the converter also reads your input that way: B3 then means Bb3.",{"q":25,"a":26},"What are 432 Hz and 443 Hz about?","440 Hz is the international standard (ISO 16). Many orchestras tune slightly higher to 442 or 443 Hz, baroque ensembles often lower to 415 Hz. 432 Hz is an alternative tuning; there is no scientific evidence for the special effects often claimed for it.",1792323198892]