Online Tone Generator: Sine Wave & Audio Frequency Generator

Online Tone Generator

Generate a continuous pure tone at any frequency between 20 Hz and 20,000 Hz. Use the slider, number input, or note picker to set the frequency, then press Play Tone. The tone plays until you press Stop.

Waveforms

• Sine: Pure tone with no harmonics. The clearest and most neutral waveform.
• Square: Rich in odd harmonics; sounds hollow or buzzy.
• Sawtooth: Contains all harmonics; sounds bright and edgy.
• Triangle: Weaker harmonics; similar to sine but slightly warmer.

Common uses

• Tuning instruments to A=440 Hz.
• Testing speaker frequency response.
• For binaural beats, use Binaural Beats, which generates stereo left/right carriers. This page plays one mono oscillator.
• Teaching acoustics and psychoacoustics.
• Solfeggio and alternative tuning exploration.

Privacy

All sound generation happens in your browser using the Web Audio API. No audio is recorded, stored, or transmitted.

Waveform types and harmonics

The timbre of a tone - why a violin and a flute sound different at the same pitch - is determined by its harmonic content:

• Sine wave: the purest tone. Contains only the fundamental frequency (1f) with no harmonics. Used in audiometric testing and tuning.
• Square wave: contains only odd harmonics at diminishing amplitude: 1f, 3f, 5f, 7f, … Sounds hollow and buzzy, like a clarinet or old video game audio.
• Sawtooth wave: contains all harmonics (1f, 2f, 3f, …). Sounds bright and edgy; the basis of many synthesizer leads and string pads.
• Triangle wave: contains only odd harmonics like the square wave, but they fall off much faster (at 1/n²). Sounds softer than a square wave; similar to sine but with slight warmth.

Frequency perception

Human hearing spans approximately 20 Hz to 20,000 Hz, but sensitivity is not uniform:

• 1–4 kHz: the range of highest sensitivity, corresponding to the vocal formant range. The ear amplifies these frequencies naturally.
• Below 200 Hz: can feel more like vibration than a clear pitch, and small speakers may not reproduce it faithfully.
• Above 8 kHz: audibility varies by listener and playback equipment. Do not raise the volume to try to hear a high-frequency tone.

Musical note reference (A4 = 440 Hz)