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Device test · Audio

Tone Generator

Dial in any frequency from 20 Hz to 20 kHz and play it as a continuous sine, square, triangle, or sawtooth wave. The tone is synthesized by your own browser — nothing is downloaded and nothing leaves your device.

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Hz · log scale
Waveform

Sustained pure tones can damage hearing. Start at a low volume and raise it gradually — especially with headphones or earbuds — and expect square and sawtooth waves to sound much louder than a sine at the same volume setting, because they carry far more energy.

How this test works

This page synthesizes a continuous test tone at the exact frequency you dial in, anywhere from 20 Hz to 20 kHz — the conventional span of human hearing. A steady tone is a sharper diagnostic than music: it holds one point of the spectrum still so you can hear precisely where a speaker fades out at the bottom of its range, where a cabinet or desk starts rattling, or whether the left and right drivers behave the same. The readout shows the commanded frequency, waveform, and volume at all times.

The tone comes from the Web Audio API's oscillator, which your browser synthesizes digitally at the audio hardware's sample rate — typically 44.1 or 48 kHz — so the frequency you set is the frequency handed to the digital-to-analog converter, accurate to a small fraction of a hertz. The slider is logarithmic, matching how pitch perception works: equal slider movements multiply the frequency instead of adding to it, giving the low octaves as much travel as the high ones. Every live change — frequency, volume, starting, stopping — is applied as a short ramp of roughly 20 milliseconds rather than an instant jump, because a discontinuity in the waveform produces an audible click that has nothing to do with your equipment.

What actually reaches your ears is outside this page's control or knowledge. Consumer speakers roll off steeply below roughly 80 Hz, so a 30 Hz tone may be silent or produce only harmonic distortion an octave up — absence of sound is not proof of a broken speaker. At the top of the range, inexpensive DACs and Bluetooth codecs can alias or collapse, adding artifacts the oscillator never produced. And because the output level is uncalibrated, this page cannot measure loudness, frequency response, or anything about your hearing — it generates the stimulus; judging what you hear is up to you.

Frequently asked questions

What frequencies should I use to check speakers or a subwoofer?
Work through the range in stages. Most full-size speakers hold output down to somewhere between 50 and 80 Hz, and dedicated subwoofers reach 30 Hz or lower, so sweep the low end slowly and note where the tone fades. Around 500–2,000 Hz listen for buzzes and cabinet rattles, which show up clearly on a steady tone. Then step through 8–15 kHz to confirm the tweeter output stays clean rather than harsh or absent.
Why does the square or sawtooth wave sound so much louder than the sine?
A sine wave concentrates all of its energy at the single frequency you set. Square and sawtooth waves add a stack of harmonics above that frequency, so at the same volume slider position they push far more total energy at your ears and sound dramatically louder and harsher. Turn the volume down before switching waveforms, not after.
I hear nothing at some frequencies. Is my speaker broken?
Not necessarily — silence usually means you have reached the edge of what the playback chain reproduces, not a fault. Small speakers commonly produce nothing usable below about 80 Hz, and many devices weaken well before 20 kHz. Before suspecting hardware, try the same frequency on a second device or a pair of wired headphones; if only one device goes quiet at a frequency the other plays, that difference is worth investigating.
Is this a hearing test?
No, and it cannot be used as one. This page is not a hearing test and cannot diagnose hearing loss or any other condition: the output level is uncalibrated, and how far into the high frequencies anyone hears varies with age, equipment, and volume. Nothing you do or do not hear here carries medical meaning. A real hearing assessment uses calibrated equipment administered by a qualified professional.
Can a continuous tone damage my speakers or headphones?
At moderate volume, no — drivers handle steady signals fine. The risk is sustained loud tones: unlike music, a continuous tone has no quiet passages, so it heats a driver's voice coil steadily, and deep bass played loudly through small speakers can push the cone past its limits. Keep the level moderate and stop immediately if you hear distortion, buzzing, or flapping.

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