EZTone at a glance
EZTone is a free online tone generator and sine wave generator that plays any frequency from 1 Hz to 20,000 Hz in your browser. It works on desktop and mobile, needs no sign-up, and never uploads audio.
- Precise frequency control: slider, exact Hz input and ±1, ±10, ±100 Hz fine-tune buttons.
- Four waveforms: sine, square, sawtooth and triangle.
- Sweep generator: linear or logarithmic glides between any two frequencies.
- Presets: 440 Hz A4, 432 Hz, 100 Hz bass test, 1,000 Hz reference and 10,000 Hz treble test.
- Mixer and scope: volume in dB, left/right pan and a live waveform display.
- Private by design: sound is synthesized locally with the Web Audio API.
What is an online tone generator?
EZTone is a free online tone generator and frequency generator that creates pure audio tones directly in your browser. Choose any frequency from 1 Hz to 20,000 Hz, pick a waveform and press Play. The sound is synthesized live with the Web Audio API, so there is nothing to download and nothing is sent to a server.
Common uses
- Tuning instruments with a 440 Hz A4 tone.
- Using it as a speaker test tone for woofers, tweeters and headphones.
- Finding room resonances and rattles with bass tones.
- Checking your own high-frequency hearing range.
- Teaching acoustics, waves and harmonics.
Sine, square, sawtooth and triangle waves
Sine
A single pure frequency with no harmonics. Best for speaker tests and hearing checks.
Square
Hollow and buzzy, made of odd harmonics. Useful for spotting distortion and clipping.
Sawtooth
Bright and rich, with both odd and even harmonics. A classic synthesizer sound.
Triangle
Softer than a square wave, with weak odd harmonics. Between sine and square in tone.
How to test speaker frequency response
- Set the volume low and select the sine wave.
- Run a sweep from 20 Hz to 20,000 Hz over 20 seconds or more.
- Listen for rattles, buzzing, distortion, dropouts or sudden changes in loudness.
- Check bass with 40–100 Hz tones and treble with 8,000–16,000 Hz tones.
- Use the pan control to check left and right channels one at a time.
| Range | Frequencies | What you hear |
|---|---|---|
| Sub-bass | 20–60 Hz | Felt more than heard |
| Bass | 60–250 Hz | Kick drums, bass guitar |
| Midrange | 250 Hz–4 kHz | Voices and most instruments |
| Treble | 4–20 kHz | Cymbals, air and detail |
Frequently asked questions
▸What is an online tone generator used for?
An online tone generator produces pure audio tones at a chosen frequency. People use it to tune instruments with a 440 Hz A4 reference, test speakers, headphones and subwoofers, find room resonances, check hearing range, and run audio experiments.
▸What is the difference between sine, square, sawtooth, and triangle waves?
A sine wave is a single pure frequency with no harmonics. A square wave has a hollow, buzzy sound made of odd harmonics. A sawtooth wave is bright and rich, containing both odd and even harmonics. A triangle wave is softer than a square wave, with weak odd harmonics.
▸How to test speaker frequency response?
Start at a low volume, play a sine wave, and run a sweep from 20 Hz to 20,000 Hz. Listen for gaps, rattles, distortion or sudden volume changes. Test the bass with 40 to 100 Hz tones and the treble with 8,000 to 16,000 Hz tones. For measured results, record the sweep and analyze it with a measurement microphone.
▸Is the 432 Hz tone really a healing frequency?
There is no solid scientific evidence that 432 Hz has special healing effects. It is a popular alternative tuning to 440 Hz, and some people simply prefer how it sounds. EZTone includes it as a preset so you can compare it with 440 Hz yourself.
▸How do I use EZTone as a sine wave generator?
Open EZTone, keep the Sine waveform selected, set any frequency from 1 Hz to 20,000 Hz with the slider or the exact-frequency box, and press Play. A sine wave is the purest tone and the best choice for speaker tests and hearing checks.
▸Is EZTone free and private?
Yes. EZTone is free, needs no sign-up, and synthesizes sound entirely in your browser with the Web Audio API. Nothing is uploaded or recorded.