Tone Generator

Tone Generator makes test sounds on the spot. Play a sine, square, triangle or sawtooth wave at any frequency from 1 Hz to 22,000 Hz, pick a musical note to tune an instrument, sweep across a range to find a rattle in your car or the limits of a speaker, or fill a room with steady white, pink or brown noise.

Frequency is set by a slider that spreads each octave evenly, an exact number box that takes decimals, semitone and octave buttons, or a note list from C0 to B8 with your own tuning for A4 (432 Hz, 442 Hz and so on). Binaural mode sends a slightly different pitch to each ear for headphone listening, and a balance slider moves any tone to the left or right speaker to check your wiring.

The sound is made by your browser as you listen, with a live oscilloscope showing its shape. Volume starts low on purpose. When you have what you want, save it as a 16-bit WAV file of the length you choose. A playful hearing check climbs or falls slowly so you can find the highest and lowest notes you and your speakers can manage. It is not a medical test.

1. Choose a tab: Tone, Sweep, Noise, Binaural or Hearing check.
2. Set the sound: drag the frequency slider or type an exact number, pick a note, or fill in the sweep’s From, To and Over boxes.
3. Press Play. Change the frequency, waveform, Volume or Balance while it plays and the sound follows smoothly.
4. Optionally pick a time under “Stop after” so it ends on its own.
5. To keep it, type a Length in seconds, choose a sample rate and press Download WAV.

• Sine, square, triangle and sawtooth waves from 1 Hz to 22 kHz, with exact decimal input.
• Note picker from C0 to B8, a read-out of the nearest note and how many cents off it is, and adjustable A4 tuning from 400 to 480 Hz.
• Sweeps between any two frequencies over half a second to ten minutes, logarithmic or linear, once, looping or up and down.
• White, pink and brown noise in stereo.
• Binaural beats from 0.5 to 40 Hz on a base pitch you choose, with the left and right ear frequencies shown.
• Balance control, a “Stop after” timer and a live oscilloscope.
• Gentle default volume and a clear warning when the level gets high.
• WAV download of up to ten minutes at 44.1, 48 or 96 kHz, mono when both sides are the same.

• Turn the volume down before putting headphones on, then raise it slowly. High pitches can harm hearing before they hurt.
• Pink noise is the usual choice for balancing speakers: play it, then walk around the room listening for boomy or dull spots.
• A slow logarithmic sweep from 20 to 200 Hz is a quick way to find which bass note makes a shelf, window or car panel buzz.
• On an iPhone, if you hear nothing, check the volume buttons; the page asks Safari to play even with the ring switch on silent.
• For a tuning reference that never wobbles, download a WAV of the note and play it on loop from your music app.