Tone generator

Generate a tone in three steps

1. Type a frequency or move the slider, or pick a preset such as 440 Hz or 1 kHz.
2. Choose a sine, square, sawtooth, or triangle wave, and press play with the volume low.
3. Raise the volume slowly, run a sweep if you need one, and download a WAV of 1 to 60 seconds.

What you can use a tone for

A steady tone is one of the most useful signals in audio. Musicians tune to 440 Hz, the A above middle C. Engineers send a 1 kHz tone through a mixer or recorder to set levels. A 100 Hz tone checks whether a subwoofer or a pair of headphones reproduces bass, and a sweep from low to high finds rattles in a car door or a desk, or the point where your speakers stop producing sound. The 50 and 60 Hz presets reproduce mains hum, the drone of the electricity supply, so you can recognize it in your own recordings. High tones at 10 or 15 kHz show the upper limit of your speakers, and of your hearing on that day.

How the generator works

Playback uses the Web Audio API built into your browser. An oscillator produces the waveform at the exact frequency you choose, and a gain control sets the volume, so the tone starts instantly and changes smoothly when you move the slider. The sweep glides the oscillator from a start frequency to an end frequency over the duration you set. The WAV download is rendered in your browser too: the tool computes the samples for the length you choose, from 1 to 60 seconds, and saves them as an uncompressed file you can import into an editor, a test setup, or a sampler. Nothing is streamed from a server.

Choosing a waveform

A sine wave is a pure tone with a single frequency, and it is what you want for tuning, testing, and listening checks. A square wave adds the odd harmonics, which makes it buzzy and loud for its level, a bit like an old video game. A sawtooth contains every harmonic and sounds bright and brassy; synthesizers use it as a starting point. A triangle wave has the same odd harmonics as a square, but they fade quickly, so it sounds soft and close to a sine. For any measurement, use sine, because the extra harmonics of the other shapes reach frequencies far above the one you typed.

Safety and limits

Begin with the volume low and raise it a little at a time. High frequencies at high volume can damage your hearing and blow the tweeters in small speakers, and a pure tone becomes tiring quickly. Phone and laptop speakers cannot reproduce deep bass, so a 30 Hz tone may seem silent on them even though the tool is playing it; use headphones or a speaker with a woofer. The 432 Hz preset is there because people ask for it, not because it has proven effects. Because loudness depends on your device and volume setting, this is not a calibrated hearing test or a medical device.