Tone Generator

A sine wave is pure and smooth with no harmonics — it is the reference shape for tuning and hearing tests. A square wave is hollow and buzzy, rich in odd harmonics, similar to a clarinet. A sawtooth is the brightest of the four because it contains both odd and even harmonics, closer to a brass instrument. A triangle sits between sine and square: soft and flute-like.

The slider is logarithmic, not linear. On a linear scale the entire musical range from 20 Hz to 2 kHz would occupy less than a tenth of the travel and the rest would be inaudibly high. A logarithmic scale gives every octave the same amount of slider, which is how pitch actually works. Use the minus and plus buttons for fine steps.

The international standard for A4 is 440 Hz, defined in ISO 16. Some musicians and ensembles prefer 432 Hz, and baroque performance often uses 415 Hz. Set the frequency you need and play a continuous sine wave as your reference.

You can explore the limits of your hearing with it, but it is not a diagnostic tool. Adult hearing typically spans 20 Hz to 20,000 Hz, and sensitivity above 15 kHz declines noticeably after the age of about 30. Results also depend heavily on your headphones or speakers. For an actual assessment, see an audiologist.

Below roughly 40 Hz, tones are felt more than heard, and most phone and laptop speakers cannot reproduce them at all. Larger headphones or a subwoofer are needed. The oscilloscope will still show the waveform even when your speaker cannot deliver it.

The oscilloscope plots amplitude over time — it shows the shape of the wave. The spectrum analyser plots energy across frequency — it shows which harmonics are present. A sine wave gives a single spike in the spectrum; a sawtooth gives a whole series of them.