Tone Generator: Online Frequency Generator

How to use the tone generator

Pick a frequency with the slider, type an exact value, or use the step buttons, then press Play. The slider is logarithmic: every octave takes the same distance, so 20 to 40 Hz gets as much room as 10 to 20 kHz. Everything can change while the tone plays. Copy link saves the settings in a link, except the volume, so a shared link never starts loud.

Shortcuts work while a button in the tool has focus, or when nothing is focused and the tool is on screen; never while you type in a field.

Waveforms

A sine wave is a single frequency with no harmonics, which makes it the tone for hearing checks and measurements. A square wave adds the odd harmonics at 1/n of the fundamental’s amplitude and sounds buzzy. At the same peak it is about 1.5 dB more powerful than a sine (3 dB for an ideal square; the band-limited one overshoots slightly at each edge). Sawtooth has every harmonic at 1/n and sounds bright. Triangle has only odd harmonics that fall off as 1/n², so it sounds close to a sine. All four are band-limited: harmonics above half the sample rate are left out, so high tones do not fold back as unrelated whistles.

Sweeps and binaural beats

A sweep glides from a start to an end frequency. On a logarithmic sweep every octave takes the same time, which matches how we hear pitch. A linear sweep changes the same number of hertz each second, so a 20 Hz to 20 kHz linear sweep spends only 1% of its time below 220 Hz. Sweeps are the quickest way to find where a speaker’s bass or your hearing ends.

Binaural beats play one sine in the left ear and a slightly higher one in the right, such as 200 Hz and 210 Hz. Neither ear gets a 10 Hz signal, but the brain perceives a 10 Hz pulsing. You need headphones, and the effect is clearest with carriers below about 1,000 Hz and differences below about 30 Hz. Research on claims that binaural beats change mood or focus is mixed.

Hearing range and safety

Young people hear roughly 20 Hz to 20 kHz. The upper limit falls with age, and many adults no longer hear above about 15 kHz. Below 20 Hz, sound is felt more than heard, and most phone and laptop speakers produce little below 100 to 200 Hz, so you may only hear distortion there.

The volume starts at 20% (−14 dBFS). Lower your device volume before you put on headphones, and never turn the volume up to find a tone you cannot hear: when you switch back to a lower frequency it can be painfully loud, and inaudible high tones can still damage tweeters.

Download as WAV

Download WAV builds the file sample by sample in your browser as uncompressed PCM: 16-bit or 24-bit integer, or 32-bit float, at 44.1, 48 or 96 kHz. Both channels saves a mono file; left, right and binaural beats save stereo. The size is sample rate × channels × bytes per sample × seconds, plus a short header: 10 seconds of 16-bit mono at 48 kHz is 960,044 bytes. The peak level follows the volume slider unless you choose a fixed one, such as −18 dBFS for an EBU R68 alignment tone. A 10 ms fade at each end prevents clicks; switch it off for a seamless loop, and choose a length that holds a whole number of cycles.