What this generator makes
A tone generator is a small synthesizer with one oscillator and no keyboard. You set a frequency, which is how many times per second the air pressure completes a cycle, and the page produces a continuous sound at that pitch. Everything is calculated live by the Web Audio engine built into your browser, so there is no file, no download and no waiting.
The frequency control runs from 1 Hz to 22,000 Hz. The slider is logarithmic, which means equal distances along it equal equal musical intervals, so the span between 100 and 200 Hz takes the same room as the span between 1,000 and 2,000 Hz. You can also type an exact value when you need 523.25 and not something close. Below the number, the page prints the nearest musical note and how many cents above or below it your tone sits, which turns the generator into a quick way to check what a frequency is called.
The preset chips jump to common values: 60, 100, 256, 432 and 440 Hz, and 1, 8 and 15 kHz. The octave buttons double or halve the current number. Press octave up at 220 Hz and you have 440 Hz; press it again for 880. For musicians, that makes it easy to hear a note in several registers, and for technicians it moves a test tone to the next region without retyping.
Waveforms and the harmonics inside them
Every waveform here repeats at the same rate when you pick the same frequency, so they share a pitch, but they do not sound alike. The difference is in the overtones, called harmonics, which are extra frequencies at whole-number multiples of the base note. A mix of harmonics is what we hear as timbre.
A sine wave is the plain one. It has only the fundamental and nothing above it, which is why it sounds smooth, hollow and almost flute-like. It is the usual choice for checking a speaker, finding a room resonance or matching a pitch by ear, because there is only one frequency to hear.
A square wave jumps between high and low and holds each value. It contains only odd harmonics, the third, fifth, seventh and so on, with amplitudes falling as one over the harmonic number. The result is a hollow, buzzy, reedy sound similar to a clarinet in its low register or early video game music.
A triangle wave also has only odd harmonics, but they fall away much faster, with amplitudes dropping as the square of the harmonic number. That is why the triangle sits between a sine and a square: it has a little of the buzz, softened.
A sawtooth ramps upward and snaps back down. It carries every harmonic, odd and even, falling off as one over the harmonic number. This gives the brightest, richest sound of the four, the starting point of many synth brass and string patches. Because a sawtooth and a square have much more energy in the upper frequencies, they also feel louder and harsher than a sine at the same volume setting, so lower the volume slider when you switch to them.
White, pink and brown noise
Noise has no single pitch. It spreads energy across a range of frequencies at random, and the way it is spread gives the three colors their character.
White noise has equal energy at every frequency, so it holds far more energy per octave in the highs than in the lows. It sounds like hiss or a radio between stations. Pink noise gives equal energy to every octave, which means it falls by 3 dB per octave and sounds more balanced and natural, like steady rain or a waterfall. Brown noise, sometimes called red, drops by 6 dB per octave and is dominated by lows, like a deep rumble or a distant engine.
People use the colors in practical ways: as masking sound to cover a noisy street or a neighbor, as a stand-in for a fan when working, as a test signal for a speaker or a room, and as a source for sound design. Studio engineers use pink noise as a reference because equal-per-octave energy matches how a spectrum analyzer displays on a logarithmic axis. Anyone who finds one color tiring can switch to another, because the three differ in comfort more than in anything else.
Because noise is random, it has no exact pitch, and the frequency box and note name do not apply to it.
Binaural beats, described plainly
Switch on the binaural beat option and the page sends one frequency to your left ear and a second, slightly different one to your right. You choose the difference, anywhere from 0.5 Hz to 40 Hz. With headphones on, the two tones are heard separately, and many listeners perceive a slow pulsing at a rate equal to the gap. If the left channel is 200 Hz and the right is 210 Hz, the pulse is perceived at 10 times per second.
This pulse does not exist in the air. It is a perceptual effect created in the auditory system when two signals are combined, which is why it only works with headphones or earphones; on speakers the two tones mix in the air and you hear ordinary beating instead of a binaural beat. WaveTinker makes this tool available as a sound source and makes no claims about what the effect does for sleep, focus, mood or health.
Use a modest volume, a base frequency in the low hundreds of hertz is a common choice, and keep the difference small at first, so the sound is easy to listen to. Sessions are limited by the timer, and you can stop at any time.
About 432 Hz and other popular numbers
The 432 Hz preset gets a lot of searches. It is a pitch some musicians prefer as the reference for the note A, in place of the standard 440 Hz. It sits about 32 cents lower, a bit under a third of a semitone, which gives music a marginally darker feel. That is a matter of taste. There is no evidence that the number is physically or spiritually special, and this page treats it as one frequency among many.
The other presets are practical. 440 Hz is the concert A used for tuning. 256 Hz is a power of two, which makes it a tidy C in the scientific pitch scale used in physics teaching. 60 Hz and 100 Hz are low enough to test bass response or mains hum. 1 kHz is the traditional reference for level comparisons, and 8 kHz and 15 kHz are bright test tones for treble. Small speakers will not reproduce the lowest ones and may give you only a faint whisper, which tells you about the speaker rather than the tone.
The table in the Numbers tab lists notes with their frequencies and wavelengths in air. Wavelength is the distance the wave covers in one cycle, and it explains why low notes are hard to place and why bass builds up in the corners of a room: at 100 Hz the wave is nearly 3.5 meters long.
Useful jobs for a tone generator
Musicians use it as a reference. Play a sine at A4 and tune a string or a voice to it, or hold a drone under a scale to hear how each note relates to the root. A drone on the bottom note of a scale makes the intervals above it obvious in a way a metronome never will.
Technicians use it for equipment checks. A sine sweep by hand reveals a rattling shelf, a loose cone or a resonant desk. With the binaural option, each ear gets a slightly different frequency, which is a quick way to confirm that both sides of a pair of headphones are playing. Producers use steady tones to align levels or to check how a mix translates to small speakers.
Teachers and students use it to demonstrate pitch, beats, harmonics, the octave relationship and standing waves. Set two nearby frequencies in turn and ask which is higher, or use the binaural option to talk about how the brain combines two ears' signals.
Playing it safely
Start at a low volume and raise it slowly. A pure tone is more tiring than music, because the energy is packed into one frequency, and a sudden loud tone through headphones can hurt. Never turn the volume up in the middle of a tone, and do not leave a tone playing on a loop while you walk away. The timer is there for this: 10 seconds is plenty for most checks.
Very low frequencies can push a small speaker beyond its limit and distort it or damage it, and very high ones can be uncomfortable even when they seem quiet. If anything feels painful, stop immediately. Judge by comfort, not by how loud the tone seems, because a very high or very low pitch can feel quieter than it really is.
Everything is generated inside the page. No sound is recorded or uploaded, and no microphone permission is needed.
Frequently asked questions
What is a tone generator?
A tone generator is a tool that produces a sound of a chosen frequency and waveform on demand. Instead of playing a recording, it computes the wave directly. People use it to tune instruments, test speakers and headphones, study how sound works, and make steady background noise.
How does a tone generator work?
The browser has a built-in oscillator that outputs a repeating wave at the frequency you set. A volume stage scales it, and the result is sent to your speakers or headphones. No audio file is involved. Changing the frequency or waveform changes the numbers the oscillator produces, so the change is immediate.
What is a tone generator used for?
Common uses are tuning to a reference note, checking whether a speaker or headphone channel works, finding room resonances, creating masking noise, demonstrating physics and music theory in class, and producing test signals for sound design. It is a utility, not a musical instrument, so it plays one steady pitch at a time.
How do I generate binaural beats?
Switch on the binaural option, set a base frequency, and choose the difference between left and right, from 0.5 to 40 Hz. Put on headphones and press play. The slight difference is perceived as a slow pulse. The effect needs headphones and a modest volume, and the page makes no claims about its benefits.
What is 432 Hz?
It is a frequency, about 32 cents below the standard 440 Hz concert A, that some musicians choose as their tuning reference. Whether it sounds better is personal preference. It has no special physical properties compared with other tunings, and you can play it with the 432 preset and compare it directly with 440.
Is it safe to play loud test tones?
Loud steady tones are tiring and can be harmful through headphones, so begin with the volume low and raise it gradually. Avoid very high or very low frequencies at high volume, since they can strain small speakers as well as your ears. Use the timer, and stop if anything feels uncomfortable.