Online Tone Generator

Online tone generator: start with a quiet sine wave

An online tone generator plays a steady frequency through the browser. Use it for pitch matching, a simple signal-path check, or a direct comparison between waveforms. It is not a calibrated sound-level meter, hearing test, or loudspeaker certification tool.

The fastest safe method

1. Turn down the device, amplifier, or headphones before playback.
2. Enter a frequency from 20 to 20,000 Hz and select Sine.
3. Set Output level near the bottom of its range, then choose Play tone.
4. Raise the level only enough to make the comparison.
5. Choose the same button to stop before changing headphones, speakers, or outputs.

The page also shows the nearest equal-tempered note. That label is an orientation aid: the frequency in Hz remains the actual oscillator setting, even when it lies between two named notes.

Worked example: 440 Hz through four waveforms

At 440 Hz, a sine wave contains one fundamental frequency and sounds comparatively plain. Keep the frequency and output level fixed, then try Triangle, Square, and Sawtooth. The triangle adds weaker odd harmonics; the square has stronger odd harmonics; the sawtooth contains a broad harmonic series. The pitch center remains A4, but brightness and edge change markedly.

Do not compensate for a waveform that sounds less prominent by making a large volume jump. Loudness depends on spectrum, playback hardware, room, and hearing sensitivity. Make short comparisons at a cautious level and return to sine when the task is a clean reference pitch.

Pitch matching and beats

To match an instrument, start the generated tone quietly and sustain the instrument near it. Two close frequencies produce beats: a periodic rise and fall in level. The beat rate slows as the pitches approach. This can provide an audible check that does not depend on watching a tuner display.

A low-frequency setting may not emerge cleanly from a small speaker. The hardware can add harmonics, rattles, or distortion while the oscillator itself remains correct. At the upper end, a tone can feel piercing even at modest power. The browser control gives no acoustic sound-pressure reading at the ear.

When playback fails or sounds wrong

• No sound: check device volume, muted browser tabs, output routing, and whether another app has taken the device.
• Clicks at start or stop: use the page button rather than repeatedly reconnecting hardware during playback.
• Wrong apparent pitch: inspect speaker range and distortion before changing the frequency.
• Harsh sound: return to sine, lower output, and shorten exposure.
• Stuck audio: press Stop and leave the page if necessary; audio also stops when the page closes.

Use the tone as a controlled signal

For a basic signal-path check, begin at 440 Hz with a sine wave and low output. Confirm the browser, system output, interface, amplifier, and speaker one stage at a time. If the signal disappears after one connection changes, restore the last working stage before touching frequency or waveform. This locates a routing fault without confusing it with speaker range or pitch perception.

For a filter comparison, keep frequency, waveform, and digital level fixed while changing one filter control. A sawtooth makes harmonic attenuation easier to hear because it starts with many upper partials; a sine wave can show whether the filter or another stage adds distortion. Match levels cautiously. A brighter spectrum may seem louder even when the generator gain has not changed.

Short playback is enough for most reference tasks. Note the chosen frequency and waveform, stop the tone, make the instrument or equipment change, then replay under the same conditions. Continuous exposure adds no information when the question is a simple before-and-after contrast. If discomfort, ringing, pain, or unusual hearing occurs, stop immediately and do not treat the generator as a diagnostic test.

Do not sweep rapidly across the full frequency range at high output. If the task is finding a resonance or rattle, use short steps, begin quietly, and pause between them. A room, enclosure, or loose object can respond strongly at one setting even when neighboring frequencies seem modest. Note the frequency where the behavior returns, then stop playback before touching hardware. Electrical repair, hearing symptoms, and calibrated acoustic testing remain outside this browser tool.

For written test notes, save frequency, waveform, output path, and the device that reproduced it. Those details make a later comparison meaningful without pretending the digital level describes acoustic loudness.

Safety, browser limits, and related tools

Output level is a digital gain control, not a measurement of decibels. Keep both level and duration modest, particularly with headphones. The World Health Organization’s safe-listening programme explains why exposure level and time matter. Browser audio is implemented through the Web Audio API.

Use the note frequency calculator to convert note, octave, MIDI number, and wavelength without continuous playback. Return to all Sound Lab tools for tuning and ear-training tasks.