Set a frequency, choose a waveform, then press Play.
tone-440Hz-sine-5s.wav
Tip: press spacebar to play or stop. Switching tabs pauses the tone automatically.
The simplest audio tool there is. One frequency, dead steady, holding pitch as long as you let it. Engineers call this a pure tone. Anyone who's ever held a tuning fork up against a piano has used the analog version. The use cases stack up fast. Speaker tests, hunts for room resonances, lining up audio gear, tuning an instrument, or just curiosity about what 1 kHz sounds like with nothing else in the way. Why a known waveform, though? Because anything strange your speakers do (a buzz, a rattle, a sudden dead spot) has to be coming from the gear or the room, not the source. Worth knowing: the whole tool runs in your browser through the Web Audio API. Nothing to install.
Sine is the simplest of the four. One frequency, no harmonics, smooth like a flute or a tuning fork. A square wave? That's a sine plus all of its odd-numbered harmonics (3rd, 5th, 7th, on up the line) at fading strength. Hence the buzzy, slightly cartoonish character. The 8-bit game soundtracks of the '80s ran on square waves, and you can still hear the texture all over chiptune today. Triangle keeps only the odd harmonics too, but they roll off much faster. Result: somewhere in the middle. Mellower than a square, brighter than a pure sine. Sawtooth carries every single harmonic, odd and even alike. Which makes it the harshest of the four — and the foundation of classic synth strings, brass patches, acid-bass lines, all of that. Flip between waveforms at the same frequency and the difference in harmonic content shows up instantly in your ears.
Concert pitch is A4 = 440 Hz. ISO 16 set that as the standard back in 1955, and most modern orchestras tune to it without thinking. But "standard" has always wandered. Plenty of European symphony orchestras tune slightly sharper (442 or 443 Hz is common) for a brighter string sound. Period-instrument groups go the other way. Baroque ensembles usually settle on A4 = 415 Hz, and classical-era performers tend to sit closer to 430. Pitch drifted upward through the whole of the 19th century, sometimes hitting 460 Hz in opera houses, before international standardisation pulled everyone back into line. Tap the 440 Hz preset to hear concert A right now.
Yes — and honestly, it's one of the fastest ways to find problems. Start the volume low. Then drag the frequency slowly upward from 20 Hz, listening for anything off — a buzz, port chuffing, a sudden jump in level, a rattle somewhere in the cabinet. A sine sweep is unforgiving in the best way. Anything loose ends up giving itself away. For something more rigorous, open our Sound Spectrum Analyzer in another tab, run pink noise through your speakers, and let a microphone watch the result. That captures the whole signal chain (room and all). It's more revealing than a single tone, but harder to read at a glance.
A slow sine sweep tells you a lot. The trick is to keep the volume modest, stay with the sine wave, and walk the slider upward from 20 Hz. So what's the giveaway? A sudden level drop, a buzz from the cabinet, or the tone simply turning muddy at certain spots. For a subwoofer's lower limit, sweep from 20 Hz up to roughly 80 Hz. Listen for the first point where the tone sounds clean (not chuffy, not distorted). That's the bottom edge. Cabinet resonances usually show up as a sympathetic buzz at one or two specific frequencies. Tap ×½ and ×2 from there to confirm the offending tone and any harmonics riding along.
Yep. Click Download Sample next to the Play button, choose a length (1, 5, 10, or 30 seconds), and out comes a standard 16-bit WAV at 44.1 kHz, mono. The file matches whatever frequency and waveform are dialled in right then. Short fades at each end keep playback from clicking. WAVs play in basically every audio tool, so the file drops straight into Audacity, Logic, Reaper, or a video timeline as a reference tone, a tuning track, or a calibration source. Heads up — it's all generated locally in your browser. Nothing leaves the page.
Yes. Copy Link drops a URL onto your clipboard. That URL captures three things: the current frequency, the waveform, and the stereo balance (the channel pan, basically). Send it wherever. A collaborator, your future self, a tech support thread — whoever opens it lands on the exact same tone settings. There's no autoplay. The recipient still has to press Play, because nobody likes a loud surprise out of their speakers. Quick note: the link's great for confirming reference tones across studios, walking a tech support call through a speaker test, or pinning down a specific frequency you've been comparing against a piece of gear.
Yes — there's more than one path to a precise frequency. Shift+arrow nudges by 1 Hz. Ctrl+arrow steps in 0.1 Hz. And Ctrl+Shift+arrow drops that to 0.01 Hz, which is honestly overkill for most jobs. The ×½ and ×2 buttons each jump a clean octave at a tap, handy when you're comparing related pitches without doing math. For exact musical pitches, the Note dropdown snaps straight to equal-tempered values like A4 = 440 Hz. All of which comes in useful for matching a reference tone against gear, tracking down something you keep hearing in a recording, or sitting on a precise pitch for a while.
Phase Test plays the same tone through both speakers, but with one channel inverted 180° out of phase. On a correctly wired pair, the result is a wide, hollow sound that won't lock onto any centre image. The two speakers are partly cancelling each other in the air between them. What if you hear something else entirely? Say, a strong, focused sound parked right in the middle? Then the polarity is reversed somewhere on your setup — usually a swapped + and − wire on one of the speakers. As sanity checks go, this one's quick. And it catches an embarrassing number of DIY wiring mistakes.
The standard human hearing range is 20 Hz to 20 kHz. In practice, the two extremes get used very differently. Below 30 Hz the vibration is physical — your chest registers it more than your ears do. And that's why subwoofer setups care so much about floor coupling and seating position. Sensitivity peaks around 2 to 5 kHz. That's where speech consonants live. It's also the band where the harshest edge of audio distortion tends to sit. Above 18 kHz, the territory becomes mostly test signals, calibration cutoffs, and high-frequency artefacts in lossy audio compression.
Set the volume to moderate. Switch to the sine wave, then sweep the slider slowly from about 30 Hz up to 200 Hz. Listen carefully. When you hit a room mode the tone gets noticeably louder (sometimes uncomfortably so), and walking around the room changes the apparent loudness almost as dramatically. Note that frequency. Most domestic rooms have audible modes between 30 Hz and 150 Hz. Those modes tie to the longest dimension via the formula f = 343 / (2L). For a visual check, watch our Spectrum Analyzer with a microphone at the listening position while the same tone plays. Peaks mark where the room reinforces. Dips mark cancellations.
The ear isn't flat. Fletcher-Munson equal-loudness contours (later refined as ISO 226) lay this out. Sensitivity peaks somewhere between 2 and 5 kHz, then drops off toward both extremes. So at conversational volume, a 50 Hz tone needs to be roughly 15 to 20 dB louder than a 1 kHz tone to feel equally loud. A 15 kHz tone? Louder still. That's why mixing engineers stick to one consistent monitor level — the bass-treble balance shifts the second you nudge the volume knob.
Most speakers can't physically produce clean sub-bass. The reason? Cones have to travel a long way to radiate a 30 Hz tone. On a small driver, "a long way" means hitting the limits of its excursion (the cone bottoms out) or driving the bass-reflex port hard enough to chuff. The result is buzzing, port wind noise, or the tone breaking into a higher-pitched rattle. Subwoofers exist for exactly this reason — a 4-inch laptop driver was never going to do that work cleanly. So if a tone sounds rough, just try it quieter. When the distortion cleans up, you've found the speaker's headroom limit.
Modest does it. The yellow strip at the top covers the listener-side reasons to stay quiet, and the same logic runs straight to your gear. Sustained loud sine tones are surprisingly hard on tweeters. They'll loosen cabinet joints over time. They'll clip the headphone amp on most laptops well before anything sounds genuinely "loud." If you're testing a speaker, find the level where the tone still sounds clean — and stop there. Rule of thumb? If you'd have to raise your voice to talk over it, it's too loud.
What follows: a quick lookup of test tones people actually use, plus what each one's good for in practice. Tap any preset above to land on a value. Off the list? Type the value into the frequency box.
| Frequency | What it's good for |
|---|---|
| 20 – 60 Hz | Sub-bass territory. Subwoofer tests, kick-drum punch, low-end room modes. |
| 50 / 60 Hz | Mains hum (depends which side of the Atlantic you're on). Useful when you're hunting a ground loop. |
| 100 Hz | Bass-speaker test territory; sits right at the lower edge of an adult male voice. |
| 261.63 Hz | Middle C (C4). Smack in the centre of a piano keyboard. |
| 440 Hz | Concert pitch (A4) — the orchestral and instrument tuning reference. |
| 1 kHz | The reference tone for audio levels, broadcast line-up, and meter calibration. |
| 2 kHz | Speech intelligibility lives here. Snare-drum body and presence too. |
| 4 kHz | Where the ear is most sensitive. Also the edge of vocal sibilance. |
| 8 kHz | Sibilance and brightness in vocals; cymbal sheen, plus general air. |
| 14 – 17 kHz | Top of the audible range. Cymbal shimmer, reverb tails, audio test signals. |
| 19 – 20 kHz | Edge of the audible range. Mostly test tones and high-frequency cutoffs in audio gear. |
Want to see what your generated tone looks like across the frequency spectrum? Open our Sound Spectrum Analyzer in another tab while a tone is playing here. You'll see the fundamental clearly, plus the harmonic stack that square, triangle, and sawtooth waves stack up on top — a quick way to hear and see the difference between waveforms at the same time. The downloaded WAV samples drop straight into the analyzer too, if you'd rather load the file than play it live.