How to Use an Online Tone Generator (Free)

An online tone generator like the Vocal Cut Tone Generator plays one steady frequency through your speakers or headphones. That is handy when you're testing gear, checking that left and right are wired correctly, tracking down a buzzing panel, or tuning against A4 = 440 Hz. Here's the short version: set the volume low, pick a frequency, choose a sine wave, press play, and only then turn it up. The rest of this guide covers which frequency to use for each job and why the waveform matters.

The tone is generated locally in your browser with the Web Audio API. Your audio never leaves your device.

How to use the tone generator, step by step

1. Turn your system volume down first. The tool opens at 440 Hz, sine wave, 20% volume. That's a sensible default, but the 20% sits on top of whatever your computer is already set to.
2. Pick a frequency. Drag the logarithmic slider, which spans 20 Hz to 20 kHz, or type an exact value in the Hz box. You can also tap a preset: 60, 100, 250, 440, 1000, 4000, 8000, 12000 or 15000 Hz.
3. Choose a waveform. You get sine, square, sawtooth and triangle. Start with sine.
4. Press play and raise the volume slowly until the tone is just clearly audible. You rarely need more than that.
5. Use the balance slider to move the tone into the left or right channel when you want to test one side at a time.
6. Read the note display. It shows the nearest musical note and how many cents (1/100 of a semitone) above or below that note you are, relative to A4 = 440 Hz.
7. Download a WAV if you need a file. Choose 5, 10, 30 or 60 seconds. You get a 48 kHz stereo WAV named something like tone_440hz_sine_10s.wav, with 10 ms fades at each end so it starts and stops without a click.

Picking a frequency: what the numbers mean

Frequency is how many times the waveform repeats each second. Low numbers are bass and high numbers are treble. If the units are new to you, What Are Audio Frequencies? covers the basics, and The Audible Frequency Range explains where the 20 Hz to 20 kHz figures come from.

Loose landmarks for the presets:

• 60 and 100 Hz: deep bass. Useful for subwoofers and for finding rattles.
• 250 Hz: low mids, where the body of most voices and instruments sits.
• 440 Hz: concert A, the standard tuning reference.
• 1000 Hz: the classic test tone. It's easy to hear and sits in the middle of the range.
• 4000 and 8000 Hz: presence and brightness. Your ears are very sensitive here, so these presets sound louder than you'd expect.
• 12000 and 15000 Hz: the top end. Many adults hear these faintly or not at all.

The slider is logarithmic because pitch works that way. Each doubling of frequency is one octave, so 100 to 200 Hz sounds like the same step as 1000 to 2000 Hz. A linear slider would cram all the bass into the first sliver.

Picking a waveform: sine first, the others on purpose

A sine is a pure tone with a single frequency and no harmonics. For most jobs, a sine tone generator is what you want: when you hear a buzz or a rattle, you know it came from the gear and not from the signal.

The other three add harmonics, which are extra frequencies stacked above the one you chose. What Is a Waveform? goes deeper, but in practice:

• Triangle has a few soft, odd harmonics. It's slightly brighter than a sine.
• Square has strong odd harmonics. It sounds hollow and buzzy.
• Sawtooth has every harmonic and sounds bright and harsh.

At the same volume setting, square and sawtooth sound noticeably louder and harsher than a sine because they carry far more energy up high. If you switch waveforms, turn down first.

Common jobs for an online tone generator

Speaker and headphone tests

Sweep slowly from low to high with a sine at a modest volume. Listen for the tone fading out early, which tells you where the driver gives up, and for crackle, buzz or distortion that shouldn't be there. Then compare a few presets on each speaker. A healthy pair should sound alike.

Left/right channel check

Move the balance slider all the way left, then all the way right. The tone should come only from the matching side. If it comes from the wrong side, a cable or a setting is swapped. If you hear it from both sides at the far left or far right, something downstream may be summing to mono. Mono vs Stereo Audio explains what that means.

Subwoofer and rattle hunting

Play 60 or 100 Hz, then nudge the frequency up and down with the number box. Loose shelves, window frames, car door panels and badly seated speaker grilles tend to buzz at one particular frequency. Once you find it, walk around the room and put your hand on suspects until the buzz stops. Keep the volume moderate. You need enough to excite the rattle, not a full-power sub test.

Tuning reference (A4 = 440 Hz)

Load the 440 Hz preset (concert pitch) and tune a string or a voice to it by ear. Listen for the slow "beating" between the two pitches; it slows down and disappears as they match. Because the display shows note names and cents, you can also type any frequency and see where it falls between notes. What Are Semitones and Cents? explains the units. If you'd rather have the instrument tell you when it's in tune, use the Guitar Tuner and follow How to Tune a Guitar.

Hearing-range curiosity, with care

Many people use a sound frequency generator to find the highest pitch they can still hear. That's fine as a curiosity, with two caveats. First, this is not a hearing test. Your speakers, headphones, volume and room all change the result, so it can't tell you anything medical. If you're worried about your hearing, see an audiologist. Second, high frequencies are where people hurt themselves: when you can't hear a tone well, the instinct is to turn it up. Don't. Keep the volume fixed and low, and stop when the tone fades.

Test signals for gear and recordings

Download a 1000 Hz sine WAV to check signal flow through an interface, mixer or recorder, set levels, or confirm that a plugin or cable path isn't adding noise. If your levels run hot, What Is Audio Clipping? shows what overload does to a clean tone. Because the file has short fades, it won't click when you drop it into a session. To see what the tone looks like on the way through, play it while the Spectrum Analyzer is open and a clean sine should show up as a single peak.

Rough room checks

Walk around the room while a low sine is playing. In some spots the bass gets louder and in others it nearly vanishes. Those are room modes, frequencies where sound bouncing between walls reinforces or cancels itself, and a tone makes them obvious in a way music doesn't. Treat this as a rough check rather than a measurement. For broadband testing, the Noise Generator gives you every frequency at once; What Is Brown Noise? explains one of its colours. For more step-by-step guides like this one, browse the How-To guides.

Safety: start quiet, stay quiet

• Turn volume down before every change of frequency or waveform.
• High frequencies and square/sawtooth waves sound louder and harsher at the same setting, and they're tiring to listen to.
• Protect your tweeters. A loud, sustained high tone, especially a square wave, can damage small drivers. Keep high-frequency tests short and low.
• With headphones, be extra careful. The tone goes straight into your ears with nothing to soften it.
• Never push a tone you can't hear to find out whether you can hear it louder.

Frequently asked questions

What frequency should I use to test speakers?

Start with 1000 Hz as a reference tone, then sweep from around 60 Hz up to 15000 Hz with a sine at low volume. Listen for distortion, rattles, or the tone fading out early, and compare left and right using the balance slider.

Is a sine wave or square wave better for testing?

A sine wave is better for almost all tests because it's a single pure frequency, so any buzz you hear comes from your gear. Square and sawtooth waves add strong harmonics and sound louder and harsher, so use them only on purpose and at a lower volume.

Can I use an online tone generator as a hearing test?

No. It can satisfy curiosity about which high frequencies you can hear, but the result depends on your speakers, headphones, volume and room, so it isn't a diagnosis. See an audiologist for a real hearing test, and never turn the volume up to chase a tone you can't hear.

Can I download the tone as a file?

Yes. You can download a WAV of 5, 10, 30 or 60 seconds at 48 kHz stereo, with short 10 ms fades at the start and end so it doesn't click. The file is created in your browser.

What is 440 Hz used for?

440 Hz is A4, the standard tuning reference for most Western music. Play it and tune an instrument or your voice by ear, or watch the note display to see how any other frequency compares in cents.

Why does the tone sound louder at some frequencies?

Human hearing is most sensitive roughly in the 2 to 5 kHz region, so tones there sound louder than bass or very high tones at the same setting. Your speakers also play some frequencies more efficiently than others, which adds to the effect.