Beats (Two Close Frequencies)
Play two tones a few hertz apart and watch the combined wave swell and fade — the beat you hear is the difference between the two frequencies, and you can tune it to zero.
Free to run with an account
What you can adjust
- Tone 1 frequency (f₁)
- 200 – 600 Hz
- Tone 2 frequency (f₂)
- 200 – 600 Hz
- Tone 2 amplitude (relative to tone 1)
- 0.2 – 1
- Duration
- 0.5 – 3 s
The first tone's frequency. 440 Hz is concert pitch A4.
The second tone's frequency. Tune it close to f₁ to slow the beat down — set it equal to f₁ and the beat disappears entirely.
How loud tone 2 is compared to tone 1. At 1.0 (matched volumes) the combined wave fades all the way to silence at each beat node; a quieter tone 2 leaves some wave left over even at the quietest point.
How much time to draw. A longer window shows more full beat cycles when the two tones are close together.