Advanced note frequency

How to use the advanced tool

Select a natural note on the first row or an altered note on the second row. In equal temperament, enharmonic notes are grouped, such as C♯/D♭. In non-equal temperaments, some notes can be separated, such as C♯ and D♭.

Then choose the octave, A4 reference, and temperament. The tool displays the calculated frequency in hertz. When the selected temperament differs from equal temperament, it also displays the cents difference.

Equal temperament

Equal temperament divides the octave into twelve equal semitones. In this system, enharmonic notes such as C♯ and D♭ have the same frequency.

Pythagorean temperament

Pythagorean temperament is based on ratios built from fifths. It can give different frequencies to some enharmonic notes, which is why sharps and flats can be separated in the interface.

Just temperament

Just temperament uses simple frequency ratios. It can produce very pure intervals in a given frame, but the results depend more strongly on the reference and harmonic context.

Cents difference

A cent is a unit used to measure very small pitch differences. One equal-tempered semitone is 100 cents and one octave is 1200 cents.

The displayed difference compares the calculated frequency with the equal temperament frequency. It only appears when another temperament is selected.

Synthesized sound

The sound is generated directly by the browser with Web Audio. It is not a system MIDI sound, but a simple and lightweight synthesized signal.

You can choose the waveform, adjust the volume, and use the Play button, which becomes Stop while playing. The sound is produced locally, without external audio files and without server-side processing.

Simple or advanced version?

This advanced version is useful for comparing temperaments, distinguishing some sharps and flats, or listening to a frequency. For a quick calculation in equal temperament, the simple version is more direct.

Data and privacy

Calculations and sound are handled directly in the browser. Notes, frequencies, settings, and generated sounds are not sent to the server to use the tool.