Online Tone Generator
Generate a pure sine, square, triangle or sawtooth tone anywhere across the full hearing range, sweep smoothly between two frequencies to test a speaker or headphone, or generate binaural beats with independent left and right channels — all synthesized directly in your browser.
Quick Tips Before You Start
Features
Turning a Slider Into a Sound Wave
Every tone here comes from a single Web Audio oscillator producing one of four basic waveform shapes. A sine wave is as simple as sound gets — one frequency, no overtones — which is exactly why it's the standard reference tone for calibration and testing rather than the other three. Square, triangle and sawtooth waves are all built from that same fundamental frequency plus a specific stack of harmonic overtones layered on top, and it's the relative strength of those overtones that gives each one its distinct character: square sounds hollow and buzzy, triangle rounder and softer, sawtooth brighter and more cutting.
Dragging the frequency slider while a tone is already playing doesn't stop and restart anything — the pitch glides smoothly from one value to the next using the Web Audio API's own parameter automation, which is also what keeps a slider drag from producing an audible click or stepping artifact between adjacent frequency values.
Reading a Room (or a Speaker) With a Sweep
A single fixed tone tells you almost nothing useful about a speaker's overall behavior — it can sound perfectly clean at 1kHz while hiding a resonant buzz at 340Hz or a dead spot at 6kHz that never gets tested. A sweep solves this by continuously moving through a chosen frequency range, which makes it far more likely that any real problem — a loose panel, a stressed driver, a narrow band of distortion — actually reveals itself as the tone passes through it.
The logarithmic option matters more than it might seem: pitch perception itself isn't linear, so a sweep that changes by a fixed number of Hz per second rushes through the bass and crawls through the treble, while a logarithmic sweep changes by a fixed percentage per second instead — evenly paced from bottom to top, which is the setting most audio engineers actually reach for when listening through a full range by ear.
Two Ears, One Illusion
Binaural beats work on a genuinely different principle from every other mode here — instead of one tone, two slightly different frequencies play simultaneously, one to each ear through headphones. Neither channel actually pulses or beats on its own; the rhythmic "beat" you perceive, equal to the exact difference between the two frequencies, is generated by your brain reconciling the mismatch, not by anything physically present in the audio signal itself. Play the same setup through a single speaker and both ears receive the identical mixed sound, and the entire illusion disappears.
The beat frequency is what determines which brainwave band it's associated with in popular use — Delta around 0.5-4Hz for deep sleep, Theta 4-8Hz for deep relaxation, Alpha 8-13Hz for relaxed focus, Beta 13-30Hz for alert thinking, and Gamma above 30Hz for intense concentration. Worth being upfront about: the auditory illusion itself is well documented and real, but the evidence for binaural beats reliably shifting mental state to match a given band is genuinely mixed in the research, so it's best approached as an experimental listening aid rather than a guaranteed effect.
Who Actually Reaches for a Pure Tone
Audio engineers and hi-fi enthusiasts use sweeps to listen for resonances, buzzes and dead spots when setting up or evaluating speakers. Musicians and piano tuners use a steady sine wave as an unambiguous reference pitch, since it isolates one frequency with nothing else to second-guess. Hearing-conscious listeners run a slow sweep informally to notice roughly where their own upper hearing limit sits. And a growing number of people use the binaural beat mode simply as background texture for studying, meditating or falling asleep, independent of whether the underlying neuroscience claims hold up to scrutiny.
Two Sessions With a Signal Generator
Someone setting up a new pair of bookshelf speakers runs the Full Range sweep preset at a moderate volume, listening for any buzz or rattle as the tone climbs from 20Hz through 20kHz — a loose grille or a stressed woofer usually announces itself clearly the moment the sweep passes its resonant frequency. Recording that sweep with the Audio Recorder first gives a saved reference to compare against after any change to speaker placement or room treatment.
A piano student instead switches to Single Tone, dials in exactly 440Hz, and uses it as a fixed reference pitch while tuning by ear — the nearest-note readout confirms it's landed on true A4 rather than a frequency that merely sounds close. For checking an actual instrument's pitch against a microphone rather than by ear, the Guitar Tuner handles that side of the same task.
What a Tone Generator Can't Tell You
Every frequency here is mathematically exact the moment it leaves the oscillator, but what actually reaches your ears afterward gets reshaped by your device's speaker or headphones, its volume setting, and the room it's playing in — none of which this tool can see or control. That's a meaningful limit for anything claiming precision: a sweep is genuinely useful for noticing where a speaker misbehaves, but it can't tell you the speaker's true measured frequency response the way a calibrated microphone and analysis software can.
It's equally not a substitute for anything clinical — not a hearing test, not a medical treatment, not a calibrated acoustic measurement. Treated as what it actually is, a precise, flexible signal source for testing, tuning, comparing and listening, it holds up well against dedicated hardware signal generators costing considerably more.
One more honest caveat, specifically for the binaural mode: it depends entirely on genuine left/right stereo playback reaching two separate ears. Bluetooth headphones that combine both channels into a single mono stream before transmitting — a real limitation on some older or budget devices — will quietly break the effect without any obvious sign that anything's wrong, since the tone still plays normally either way. Wired headphones sidestep that risk entirely if the effect doesn't seem to be working as expected.