What you can do with a tone generator
- Test speakers and headphones: sweep slowly from low to high and listen for rattles, buzzing or where the sound drops off.
- Check your hearing range: raise the frequency until you can no longer hear it (keep the volume moderate).
- Tune instruments: play A4 at 440 Hz as a reference pitch.
- Find room or car rattles: play low tones (30–120 Hz) to locate loose panels.
- Science lessons: demonstrate frequency, pitch, octaves and beats.
Frequencies and musical notes
| Note | Frequency |
|---|
| E2 (low E on guitar) | 82.41 Hz |
| A2 | 110 Hz |
| C4 (middle C) | 261.63 Hz |
| A4 (tuning standard) | 440 Hz |
| C5 | 523.25 Hz |
| A5 | 880 Hz |
Doubling a frequency raises the pitch by one octave, and halving it lowers it by an octave. That is why the × 2 and ÷ 2 buttons jump by octaves.
About "healing frequencies"
You may see claims that tones like 432 Hz or 528 Hz have special healing powers. There is no reliable scientific evidence for these claims. They are included as presets because people ask for them, and many find steady tones relaxing.
Testing stereo speakers? The speaker test checks left and right channels and runs a full sweep.
Last reviewed October 2026.
Frequently asked questions
What is a tone generator?
A tone generator plays a pure sound at a frequency you choose, measured in hertz (Hz). It is used to test speakers and headphones, tune instruments, check hearing range, find rattles in a car or room, and for science experiments.
What do the waveforms sound like?
A sine wave is the purest, smoothest tone. A square wave sounds buzzy and hollow, like old video games. A sawtooth wave is bright and harsh, and a triangle wave sits between sine and square.
What is the range of human hearing?
Roughly 20 Hz to 20,000 Hz for young people. The upper limit drops with age, and many adults cannot hear above 14,000–16,000 Hz. Small speakers often cannot play below about 100–200 Hz, so silence at the low end may be your speaker, not your ears.
Is it safe to play loud tones?
Start with a low volume and raise it gently. High-frequency tones can be unpleasant and loud tones of any frequency can damage hearing with long exposure. Very loud low tones can also damage small speakers.
Can I play two tones at once?
Yes. Turn on the second tone to create beats (when two close frequencies pulse together) or test binaural effects with headphones by sending one tone to each ear using the balance controls.