What is a tone generator, and is this a cable probe?

An audio tone generator creates a periodic signal at a selected frequency. This page uses the browser’s Web Audio oscillator and selected audio output. Physical cable tone generators inject a signal into wiring for a separate probe to detect; this page provides neither that hardware nor wire tracing. It also does not provide a radio encoder, native application or sampled instrument synthesizer.

How do I play a 440 Hz, 432 Hz, 40 Hz or 1 kHz reference?

Type the frequency in hertz, or a kilohertz value such as 1 kHz, select a waveform and press Play. A 440 and 1 kHz also have preset buttons. Plain decimal or scientific notation and correctly grouped thousands such as 1,000 are accepted. Invalid text stops the previous tone. These values specify an audio reference; no therapeutic effect or calibrated physical frequency is established.

Why does Play say Starting, or show an audio error?

The browser must grant and run its audio clock before a tone starts. Check the browser’s sound permission and selected output, then press Play again. Cancel start stops a pending attempt. Returning to a hidden page or a page restored from history does not restart sound automatically; press Play for a new run.

Why does the range depend on the browser sample rate?

Typing accepts a nominal 1 to 22,000 Hz and the logarithmic slider covers 20 Hz to 20 kHz. The actual context must sample faster than twice the highest selected frequency. Values at or above half its sample rate are refused rather than substituted. A 32,000 Hz clock cannot run the full 20 kHz sweep; turn Sweep off and choose a frequency below 16,000 Hz.

What do volume percent and the two Play presses mean?

Percent controls software gain with a squared curve: 50% sets gain 0.25. It is not decibels or a measured headphone/speaker level. A stopped tone above 60% requires two Play presses for the same level; changing the slider withdraws that first request. While playing, a higher requested level is held at the current ceiling until Allow confirms it. Start low; the page cannot establish a comfortable acoustic level.

Why does the waveform matter?

Sine supplies a single fundamental in the browser oscillator. Square and triangle contain odd harmonics at different strengths; sawtooth contains both odd and even harmonics. Browser synthesis and sample-rate limits affect the resulting signal. The frequency readout names the fundamental, not every harmonic or a calibrated measurement of physical sound.

What does the twenty-second sweep do?

It schedules a logarithmic frequency ramp from 20 Hz to 20 kHz, with equal time per octave. The displayed progress and finish follow the current audio clock. Hiding or leaving the page stops the run; it does not finish silently in the background. A sweep can supply an audio-system reference but cannot measure frequency response, certify a channel, identify the cause of a rattle or diagnose a fault.

What do the musical note, period and wavelength mean?

The nearest note uses equal temperament with A4 at 440 Hz: 440 Hz is A4, Middle C is 261.63 Hz, and 1,000 Hz is near B5, 21 cents sharp. Period is 1/frequency. Wavelength is 343 m/s divided by frequency, using a stated speed of sound in air at 20 degrees C. These are calculations from the selected value, not measurements of your equipment.

Why can I not hear a 15 kHz or 17 kHz reference?

The selected output, browser processing, speakers or headphones and the listener can affect what is audible. This page cannot distinguish those causes and provides no hearing test, diagnosis or tinnitus treatment. The 15 kHz and 17 kHz buttons are audio reference presets; an inaudible result does not establish a medical conclusion.

Are multiple tones, DTMF, binaural beats, random tones or files included?

This tool plays one oscillator at a time and offers one fixed frequency sweep. It does not independently generate simultaneous frequencies, telephone DTMF pairs, left/right binaural signals, isochronic pulses, random tone sequences, Shepard illusions, twelve-tone composition rows, realistic guitar/piano timbres, MIDI or ringtone/WAV files.

Is anything recorded or stored?

No microphone is opened, no audio file is uploaded and no frequency or volume input is stored. Sound is generated in the browser. The site’s privacy-controlled usage measurements contain no frequencies, levels, waveform selections, audio samples or observations about hearing or equipment.

Tone Generator

Play one browser audio frequency, choose sine, square, triangle or sawtooth, or run a twenty-second logarithmic sweep from 20 Hz to 20 kHz. Type a nominal 1 to 22,000 Hz value, use the logarithmic slider or pick A 440, Middle C, 1 kHz and other reference presets. Read the nearest equal-tempered note, period and wavelength in air. Frequencies must be below half the browser audio sample rate. Volume is a software gain setting; it is not a measured acoustic level.

Frequency440 HzA4 · sine · stopped

Wave

Frequency (Hz)

Volume: 30%

Sweep

Stopped. Press Play to hear 440 Hz, sine, at 30%.

Nearest noteequal temperament, A4 = 440 Hz
A4
Periodone cycle
2.27 ms
Wavelength in airat 343 m/s, 20 degrees C
78.0 cm
Sine wavewhat it contains
the fundamental alone, no harmonics: the purest test tone

Volume is a software setting. The percentage controls browser gain; it is not a measured acoustic level and cannot establish a comfortable headphone or speaker level. Start low. Above 60% a stopped tone needs two Play presses. Increasing a playing tone above its confirmed level requires Allow. Starts and stops use 15 ms gain ramps to reduce abrupt transitions.

Accuracy. Frequency and gain are settings for the browser audio engine, subject to its sample rate and clock. Physical sound depends on the selected output and equipment; this is not a calibrated acoustic measurement or a hearing test. Fifteen-millisecond gain ramps reduce abrupt starts and stops. The nominal typed range is 1 to 22,000 Hz; the slider covers 20 to 20,000 Hz on a logarithmic scale, so each octave takes the same width. Frequencies at or above half the browser audio sample rate are refused.

Common questions

What is a tone generator, and is this a cable probe?: An audio tone generator creates a periodic signal at a selected frequency. This page uses the browser’s Web Audio oscillator and selected audio output. Physical cable tone generators inject a signal into wiring for a separate probe to detect; this page provides neither that hardware nor wire tracing. It also does not provide a radio encoder, native application or sampled instrument synthesizer.
How do I play a 440 Hz, 432 Hz, 40 Hz or 1 kHz reference?: Type the frequency in hertz, or a kilohertz value such as 1 kHz, select a waveform and press Play. A 440 and 1 kHz also have preset buttons. Plain decimal or scientific notation and correctly grouped thousands such as 1,000 are accepted. Invalid text stops the previous tone. These values specify an audio reference; no therapeutic effect or calibrated physical frequency is established.
Why does Play say Starting, or show an audio error?: The browser must grant and run its audio clock before a tone starts. Check the browser’s sound permission and selected output, then press Play again. Cancel start stops a pending attempt. Returning to a hidden page or a page restored from history does not restart sound automatically; press Play for a new run.
Why does the range depend on the browser sample rate?: Typing accepts a nominal 1 to 22,000 Hz and the logarithmic slider covers 20 Hz to 20 kHz. The actual context must sample faster than twice the highest selected frequency. Values at or above half its sample rate are refused rather than substituted. A 32,000 Hz clock cannot run the full 20 kHz sweep; turn Sweep off and choose a frequency below 16,000 Hz.
What do volume percent and the two Play presses mean?: Percent controls software gain with a squared curve: 50% sets gain 0.25. It is not decibels or a measured headphone/speaker level. A stopped tone above 60% requires two Play presses for the same level; changing the slider withdraws that first request. While playing, a higher requested level is held at the current ceiling until Allow confirms it. Start low; the page cannot establish a comfortable acoustic level.
Why does the waveform matter?: Sine supplies a single fundamental in the browser oscillator. Square and triangle contain odd harmonics at different strengths; sawtooth contains both odd and even harmonics. Browser synthesis and sample-rate limits affect the resulting signal. The frequency readout names the fundamental, not every harmonic or a calibrated measurement of physical sound.
What does the twenty-second sweep do?: It schedules a logarithmic frequency ramp from 20 Hz to 20 kHz, with equal time per octave. The displayed progress and finish follow the current audio clock. Hiding or leaving the page stops the run; it does not finish silently in the background. A sweep can supply an audio-system reference but cannot measure frequency response, certify a channel, identify the cause of a rattle or diagnose a fault.
What do the musical note, period and wavelength mean?: The nearest note uses equal temperament with A4 at 440 Hz: 440 Hz is A4, Middle C is 261.63 Hz, and 1,000 Hz is near B5, 21 cents sharp. Period is 1/frequency. Wavelength is 343 m/s divided by frequency, using a stated speed of sound in air at 20 degrees C. These are calculations from the selected value, not measurements of your equipment.
Why can I not hear a 15 kHz or 17 kHz reference?: The selected output, browser processing, speakers or headphones and the listener can affect what is audible. This page cannot distinguish those causes and provides no hearing test, diagnosis or tinnitus treatment. The 15 kHz and 17 kHz buttons are audio reference presets; an inaudible result does not establish a medical conclusion.
Are multiple tones, DTMF, binaural beats, random tones or files included?: This tool plays one oscillator at a time and offers one fixed frequency sweep. It does not independently generate simultaneous frequencies, telephone DTMF pairs, left/right binaural signals, isochronic pulses, random tone sequences, Shepard illusions, twelve-tone composition rows, realistic guitar/piano timbres, MIDI or ringtone/WAV files.
Is anything recorded or stored?: No microphone is opened, no audio file is uploaded and no frequency or volume input is stored. Sound is generated in the browser. The site’s privacy-controlled usage measurements contain no frequencies, levels, waveform selections, audio samples or observations about hearing or equipment.

Frequency and gain are settings for the browser audio engine, subject to its sample rate and clock. Physical sound depends on the selected output and equipment; this is not a calibrated acoustic measurement or a hearing test. Fifteen-millisecond gain ramps reduce abrupt starts and stops.