Tone Generator

What is a tone generator?

A tone generator plays a single, steady sound at a frequency you choose. Instead of music or speech — which are made of many frequencies changing constantly — a tone generator produces one clean pitch, held for as long as you like. That simplicity is exactly what makes it useful: when you hear (or fail to hear) a pure tone, you learn something specific about your speakers, your room, your headphones, or your own ears.

This tool runs entirely in your browser using the Web Audio API, the same audio engine that powers games and music apps on the web. The sound is synthesised on your device in real time. There is no file to download, nothing is uploaded, and the tone exists only while it is playing.

How to use it

1. Press Play tone to start. (Browsers only allow audio after a click, so the sound engine starts on that first press.)
2. Set the frequency in hertz (Hz) — type an exact number, drag the slider across the 20 Hz–20 kHz range, or use the minus and plus buttons to step one hertz at a time.
3. Choose a waveform: sine, square, sawtooth or triangle.
4. Adjust the volume — it deliberately starts low to protect your ears.
5. The tool shows the nearest musical note to your frequency (for example, 440 Hz is A4), so you can use it for tuning too.

Frequency, waveform and volume all update live while the tone is playing, so you can sweep around and hear changes instantly.

What frequency does what?

Human hearing roughly covers 20 Hz to 20,000 Hz, and different parts of that range behave very differently:

• Sub-bass (20–60 Hz). Felt as much as heard. Useful for testing subwoofers and whether a room reinforces or cancels low notes. Many small speakers and laptops can't reproduce this range at all.
• Bass (60–250 Hz). The weight and body of music. Good for checking how full a speaker sounds and for finding rattles.
• Midrange (250 Hz–4 kHz). Where voices and most instruments live, and where the ear is most sensitive. Problems here are very audible.
• Treble (4 kHz–20 kHz). Detail, "air" and sibilance. The top of this range is the first thing to fade as hearing ages, which is why high-frequency tones are a common informal hearing check.

A few useful reference points: 440 Hz is the A above middle C (concert pitch), 1 kHz is the classic reference tone audio engineers use for level-setting, and a sweep from low to high quickly reveals which frequencies a system handles well.

Waveforms: why they sound different

At the same frequency, the shape of the wave changes the timbre — how rich or harsh it sounds — because each shape contains a different set of harmonics (overtones above the base pitch):

• Sine. The purest tone, with no harmonics at all — just the single frequency. Smooth and a little dull. Best for clean hearing tests, tuning and measuring a single frequency.
• Triangle. Soft and mellow, with only weak, quickly fading harmonics. A gentle alternative to sine.
• Square. Hollow and buzzy, containing strong odd harmonics. It sounds noticeably louder and harsher than a sine at the same volume setting, so lower the volume before switching to it.
• Sawtooth. The brightest and richest, with both odd and even harmonics. The classic raw synthesiser sound.

For most testing and tuning, start with sine — it isolates one frequency so you can be sure of what you're hearing.

Real-world uses

Testing speakers, headphones and subwoofers. Play a steady tone and listen for distortion, buzzing or a drop-out as you change the frequency. Sweeping slowly through the bass region is a good way to confirm how low your system can actually go before the sound thins out or disappears.

Finding rattles and resonances. A sustained low tone makes loose panels, furniture, car trim or speaker grilles vibrate audibly. Hold a frequency, walk around, and the offending object will often announce itself — then move up and down a little to find the exact pitch that sets it off.

Tuning instruments. Because the tool shows the nearest note and how many cents you are away from it, you can play a reference pitch (like 440 Hz for A) and tune a guitar, violin or other instrument by ear against it.

Checking your hearing range, informally. Many people are curious how high a frequency they can still hear. Starting low and slowly raising the frequency toward the top of the range gives a rough, personal sense of your treble hearing. Treat this as casual curiosity, not a test — your speakers or headphones, your volume, your environment and your device all affect the result, and none of it is calibrated; for a more structured take on the same idea, the Hearing Age Test estimates your hearing age from the highest frequency you can still detect.

Channel and wiring checks. A steady tone helps confirm left/right channels are working and correctly wired, and that a connection isn't intermittent.

A note on tinnitus and hearing

Some people use tone generators to try to match the pitch of tinnitus (a ringing or buzzing they hear), simply out of curiosity about which frequency it resembles. If you do this, please be gentle: keep the volume low, keep sessions brief, and stop if it feels uncomfortable or unsettling.

This is not medical advice and not a diagnostic tool. A web page playing tones cannot assess your hearing, and matching a pitch here doesn't measure anything clinical. If you have ringing in your ears, hearing loss, pain, or any concern about your hearing, please talk to a doctor or a qualified audiologist who can test you properly with calibrated equipment.

Hearing safety

Pure tones deserve respect. They can sound deceptively quiet at first and then become uncomfortable, and sustained loud or very high-frequency tones can genuinely harm your hearing and stress your speakers or headphone drivers. A few sensible habits:

• Start low. Begin at a low volume and raise it slowly. This tool intentionally opens with a low level.
• Keep it brief. There's rarely a reason to hold a loud tone for a long time.
• Be extra careful with high frequencies and with square or sawtooth waves, which carry more energy and sound harsher.
• Stop immediately if you feel any discomfort, and never use a tone generator at high volume around babies, pets or anyone who can't move away from the sound.

Private by design

Everything happens locally in your browser. There's no account, no upload and no recording — the tone is generated on the fly and disappears the instant you stop it or leave the page. Use it as often as you like; nothing about your session is logged or transmitted.