Tone Generator (Frequency Generator)

Make a pure test tone at any frequency from 1 Hz to 22 kHz, or at a musical note, as a sine, square, sawtooth or triangle wave. Play it continuously and change the frequency while it sounds, or download an exact WAV or MP3 file. Sweeps from one frequency to another help find rattles, room resonances and the limits of your hearing or speakers.

How to use this tool

1. Turn your volume down first.
2. Enter a frequency, or a note such as A4 or C#5, and choose the waveform.
3. For a file, set the duration (and a sweep if you want one); the player appears below. For a continuous tone choose "Play continuously" and press Calculate.
4. Use Left only / Right only to check each side of headphones or speakers.

Formula

f(note) = 440 × 2^((n − 69) ÷ 12) · period = 1 ÷ f · wavelength = 343 m/s ÷ f

n is the MIDI note number (A4 = 69, C4 = 60). Tones are rendered by the browser's band-limited oscillator, so square and sawtooth waves have no aliasing, and then scaled so the peak is exactly the chosen dBFS. A logarithmic sweep spends equal time on each octave; a linear one on each hertz. Files start and end with 10 ms fades to avoid clicks.

Example

Note E4 is 440 × 2^((64 − 69) ÷ 12) = 329.63 Hz: one cycle every 1000 ÷ 329.63 = 3.034 ms, and a sound wavelength of 343 ÷ 329.63 ≈ 1.04 m in air.