Tone Generator
Test tones, tuning references, and frequency sweeps generated locally
100% In-Browser · Private & Instant · Free Forever
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Interactive Workspace
Tone Generator
Generate a clean sine tone or a logarithmic frequency sweep and use it to test speakers, headphones, and room acoustics, to tune an instrument, or to create a known reference for another tool.
The presets cover the common jobs:
- A4 440 Hz and A4 432 Hz — tuning references for instruments and for checking a recording's pitch
- C4 261.6 Hz — middle C for ear training and pitch matching
- 50 Hz and 60 Hz — mains hum, useful for testing the rumble filter and noise remover
- 30 Hz sub — a low-frequency check for subwoofers, and for hearing where a laptop speaker gives up
- 20 Hz → 20 kHz sweep — the full audible range, for checking a playback system end to end
- 100 Hz → 10 kHz sweep — the speech band, for driver and crossover checks
How to use a sweep: play it at a moderate level and listen for frequencies where the tone suddenly gets louder, quieter, or starts to rattle. A peak in one narrow band usually means a room resonance; a rattle means something in the room or the speaker is vibrating. Do not turn the level up to compensate — a resonance that is hard to hear at low level is harmless, and the same resonance at high level is not.
Level and duration: the default is -6 dBFS for 10 seconds. Tones are generated with short fades at both ends so the file does not click when played.
Hearing safety: a continuous sine wave at high level is more damaging than music at the same perceived loudness, because all the energy sits in one place. Start quiet, raise slowly, and stop if anything feels uncomfortable. Files are decoded, measured, and re-encoded inside this browser tab. Nothing is uploaded and no result is retained after you close the page.
How It Works
Pick a signal
Choose a fixed tone or one of the two frequency sweeps.
Set duration and level
One to sixty seconds, from -60 dBFS to full scale.
Play it
Start at a low level and raise it gradually.
Download if needed
Export the tone as WAV for use in another tool.
Features
Tuning References
440 Hz, 432 Hz, and middle C, generated to the sample.
Logarithmic Sweeps
20 Hz to 20 kHz and 100 Hz to 10 kHz full-range sweeps.
Mains Hum Tones
50 Hz and 60 Hz signals for testing noise removal.
WAV Download
Export a 16-bit WAV you can loop in any player.
Tuning References and Pitch Standards
Modern concert pitch is A4 = 440 Hz, agreed internationally in the twentieth century. Not every ensemble uses it: many European orchestras tune to 442 or 443 Hz for a brighter sound, period-instrument groups often use 415 Hz for Baroque repertoire, and some contemporary producers deliberately work at 432 Hz. If you are tuning an instrument to a recording, match the recording rather than assuming 440.
The difference is small but audible when layered. A 440 Hz reference played against a 432 Hz recording beats about eight times per second, which sounds like a slow wobble rather than an out-of-tune note. That is why the pitch shifter and the analyzer both report a tuning reference: matching a sample to a project requires knowing what the project considers in tune.
Testing a Playback System Safely
The most useful test tone is a slow sweep, because it reveals problems that a single frequency hides. Play it at a comfortable level and listen for three things: a sudden boost in one frequency region, which indicates a room resonance; a rattle or buzz, which indicates something physical vibrating; and an abrupt drop, which indicates the limit of a driver or the crossover point between drivers.
Volume discipline matters more here than anywhere else in audio work. A sine wave at 90 dB SPL is delivering all of its energy to a narrow band of the cochlea, and exposure limits for pure tones are considerably shorter than for broadband sound. Keep sweeps short, keep the level moderate, and never leave a continuous tone playing while you do something else.
Files are decoded, measured, and re-encoded inside this browser tab. Nothing is uploaded and no result is retained after you close the page.
The generated WAV is a known, exact signal. That makes it useful as a reference input for other tools on this site — a 50 Hz tone through the noise remover shows you directly what the rumble filter does, and a 440 Hz tone through the pitch shifter shows you exactly how many cents a semitone shift moves the reference.
Related Tools
Pitch Shifter
Transpose a recording up or down while keeping its original length
Audio Equalizer
Ten bands from 32 Hz to 16 kHz, with presets and a spectrum view
Noise Remover
Learn the noise floor of a recording, then gate it out band by band
BPM & Key Finder
Tempo, key with Camelot code, tuning reference, and loudness measurements
Tone Generator — FAQ
Can a tone generator damage my speakers or hearing?
Yes, in two ways. A continuous sine wave concentrates all its energy at one frequency, so it can overheat a driver that would handle the same perceived loudness of music without trouble. And sustained loud tones damage hearing. Start at a low level, raise it slowly, and stop if anything sounds harsh or feels uncomfortable.
What can I test with these tones?
Speaker and headphone frequency response, the low-frequency limit of a playback system, room resonances using a sweep, and the effect of the noise remover and rumble filter using the mains hum presets. You can also use 440 Hz as a tuning reference for instruments.
Why does the sweep sound like it speeds up?
A logarithmic sweep multiplies frequency rather than adding to it, so it covers each octave in the same amount of time. Because pitch perception is logarithmic, that produces a sweep that sounds even to the ear — which is the opposite of a linear sweep, which spends most of its time at high frequencies and sounds like it rushes through the low end.
Can I use the tone generator to test my hearing?
It can tell you the highest frequency you can hear at a given level, but that is not a hearing test. Real audiometry controls the playback chain and the calibration of the transducer, which a browser on unknown hardware cannot do. Use it as a curiosity, not as a health assessment.
Why is there a fade at the start of the tone?
Starting a sine wave at full amplitude creates a click, because the waveform jumps from zero to its peak instantly. A short 20 ms fade at both ends removes that discontinuity, so the exported file starts and ends cleanly.
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