Frequency Generator
- Nearest note
- A4
- 0 cents from 440 Hz
440Hz
Preset frequencies
Waveform
Play a note
Glide from the frequency above to an end frequency over the length chosen below, evenly in pitch: every octave takes the same time. Play and the downloaded file both sweep, for testing a speaker, a room or your hearing.
Save the tone as a file
The file is made on this device at the volume you set, with a 10 ms fade at each end so it does not click.
A frequency generator that holds one steady tone
A single tone is a reference: it shows whether a speaker rattles, whether two headphones match, and which low notes a room will carry. This generator keeps one oscillator running while you change the frequency, the waveform and the volume underneath it.
The whole audible range on one slider
The slider covers 20 Hz to 20 kHz and travels by an equal distance per octave, so the bottom of the range is as easy to land on as the top.
Four waveforms, changed while it plays
Sine, square, triangle and sawtooth come from the browser's own oscillator, and the waveform can be switched without stopping the tone.
Presets, notes and a file to keep
Common reference frequencies are one press away, any note can be picked by name and octave, and the tone saves as a WAV, MP3 or FLAC file from 5 to 60 seconds long.
How it works
Play a tone in three steps
Choose a frequency
Drag the slider, press a preset, pick a note, or type the number to a hundredth of a hertz. The plus and minus buttons move by one percent for fine tuning.
Choose a waveform
Sine is the purest tone. Square, triangle and sawtooth add harmonics that make the pitch easier to place on a small speaker.
Set the volume and press play
The tone starts at a quarter volume. Stopping it fades the sound out and closes the browser's audio context.
Range, waveforms and levels
The range the generator covers, from the bottom of a subwoofer to the top of what an ear can follow.
Sine, square, triangle and sawtooth, all produced by a single oscillator.
174, 285, 396, 440, 528, 1000 and 8000 Hz are one press away, and the octave buttons move from any of them.
A tone saves as WAV, as MP3 at 320 kbps or as FLAC, 5, 10, 30 or 60 seconds long, and the file is made on this device.
Who plays a test tone
Anyone checking a speaker or headphones
Sweep the frequency and listen for a rattle, a gap at the low end, or a channel that drops out before the other one.
Musicians tuning by ear
Play 440 Hz as a reference, or use the octave buttons to reach the register of the instrument you are tuning.
Producers testing a room
Play a low tone and walk the room to find where a bass note builds up and where the same note disappears.
Frequency Generator FAQ
Keep the tone as your reference
Play 440 Hz before you tune, or leave the tone open while you check a mix on a second speaker.