Audio Signal Tone Generator
Before you start: Keep device volume low, especially before changing frequency or waveform. Do not raise volume to force an inaudible high or low tone. This is not a hearing test or calibration tool.
Audio signal tone controls
Set the exact digital tone, channel, duration and level. Nothing plays until you press Play.
Loading audio controls.
Create a deterministic reference for tracing an audio path and repeating the same test later.
Interpretation: A known digital tone helps establish whether a path carries a selected frequency and channel.
Limit: It cannot establish physical SPL, hearing ability or the isolated performance of one component in a complete chain.
Safety and privacy: No sound starts automatically. Signals and analysis stay in your browser by default. Browser dBFS is not physical SPL.
How to use this test
- Choose one variable: Set the frequency, waveform, duration, route and conservative digital level before playback.
- Keep device volume low: The dBFS setting controls the browser signal, not the physical loudness at your ear or in the room.
- Repeat the same reference: Use unchanged settings when comparing cables, devices, apps or output paths.
Choose the signal level: New references start at -40 dBFS peak. Select up to 0 in 5 dB steps, then press Play. This is WaveLocus's selectable range, not an industry standard or a physical-volume measurement. Zero is full-scale digital output; lower device volume before playback.
Reference and scope: For equipment alignment, EBU specifies a sine reference 18 dB below maximum digital coding. Use the named 1 kHz alignment option for that purpose; it is a reference exception to the regular 5 dB menu, not the default for every waveform. EBU alignment recommendation.
How tone levels are chosen
The main control sets the source sample peak. Sine, square, triangle and sawtooth can have different average levels at the same peak. The readout reports peak and RMS separately. The EBU alignment option sets a 1 kHz sine at −18 dBFS source peak without starting playback. It is an equipment reference, not a headphone calibration or safe physical listening level.
Source: EBU alignment recommendation. Read dBFS vs dB SPL to distinguish digital signal levels from physical sound pressure. Use the frequency sweep to follow a changing frequency instead of one fixed tone.
How to interpret your audio signal tone generator results
Peak and RMS differ: Peak describes the largest sample; RMS averages squared samples over the reference, including fades. Different waveforms and noise colours can have different RMS at the same source gain.
A peak guard limits the requested target: The displayed measured output takes priority over the requested setting. Do not treat an unreached RMS target as a successful match.
A frequency is faint or inaudible: Return to an ordinary reference at low physical volume. Audibility depends on the complete path and cannot establish hearing ability or calibrated frequency response.
Source: REW level-setting procedure.
Frequently asked questions
Which frequencies can the online tone generator play?
Choose a whole-number frequency from 20 to 20,000 Hz. The selected output device and browser may not reproduce every frequency. The presets provide short starting references.
Can I generate sine, square, triangle and sawtooth waves?
Yes. Select the waveform, frequency, duration, channel and digital level before pressing Play. Non-sine waves also contain harmonics, so they are not a single-frequency reference.
Why can I not hear a selected frequency?
The output path, its frequency response and your listening conditions can affect audibility. Keep volume low and return to a moderate reference such as 440 Hz. Do not use this result to judge hearing ability.
How are frequency and period related?
Frequency is cycles per second. Period is the duration of one cycle. At 440 Hz, one cycle lasts about 2.27 milliseconds. This calculation describes the signal, not how loud it sounds.
What do the left and right percentage controls change?
With Both selected, each slider attenuates its own channel from 100% down to silence. You can adjust them during playback. Match lower level sets both to the lower value, while Reset to 100% restores the reference levels. These percentages do not measure physical loudness.