Documentation
Water eject tone specification
The exact signal the water eject tool plays. All values come from one data file, so this page, the tool and the tone video always match.
This page says what the tone is. For why it uses these values, see How we measured.
Summary
| Parameter | Value |
|---|---|
| Protocol version | 1 |
| Waveform | sine |
| Cycles per session | 3 |
| Pulses per cycle | 10 |
| Pulse length | 1.5 s |
| Gap after each pulse | 0.75 s |
| Cycle length | 22.5 s (10 × 2.25 s) |
| Pause between cycles | 12 s |
| Fade in and fade out of each pulse | 10 ms, linear |
| Peak level | 1.0 |
| Tone time per session, without listen checks | 91.5 s (3 × 22.5 s + 2 × 12 s) |
1.0 is the linear gain of each pulse envelope in the browser. The phone volume and the phone's own audio processing set the real loudness. You wipe the speaker grille with a dry cloth during the pause. The More time button adds 15 s to the pause, as often as you need.
Pulse frequencies
The pulses of one cycle step up in a straight line from 150 Hz to 300 Hz. Pulse i (counted from 0) plays round(150 + (300 − 150) × i / 9) Hz. Every cycle plays the same 10 frequencies.
| Pulse | Frequency | Starts at (in the cycle) |
|---|---|---|
| 1 | 150 Hz | 0 s |
| 2 | 167 Hz | 2.25 s |
| 3 | 183 Hz | 4.5 s |
| 4 | 200 Hz | 6.75 s |
| 5 | 217 Hz | 9 s |
| 6 | 233 Hz | 11.25 s |
| 7 | 250 Hz | 13.5 s |
| 8 | 267 Hz | 15.75 s |
| 9 | 283 Hz | 18 s |
| 10 | 300 Hz | 20.25 s |
Listen check sweep
Optional, before and after the session. One sine sweep that rises exponentially from 200 Hz to 4000 Hz in 4 s, at peak level 0.5, with a 50 ms fade. It is not part of the water eject signal. It lets you compare the sound before and after.
Resonance pass (experimental)
Off by default. Turn it on with the checkbox before you start. One sine sweep that rises exponentially from 450 Hz to 900 Hz in 4 s, played 2 times, at peak level 0.9, with a 20 ms fade.
How the browser plays it
- The tool creates its audio context only after a tap, because browsers block sound that starts without one.
- Each pulse uses a new sine oscillator, so every pulse starts at zero phase. A gain envelope fades it in and out.
- All pulses go through one master gain to the speaker. All timing runs on the audio clock of the browser, not on page timers, so a slow page does not change the rhythm.
- When you tap Stop, the master gain fades to silence in 30 ms, then the oscillators stop.
- The tool runs at most 3 sessions. After the third, the result tells you to stop and let the phone dry.
What a web page cannot control
A web page cannot choose the speaker, set the phone volume or turn off the phone's speaker protection. For what this means for the result, see Does the water eject sound work?. For the limits of each browser, see Browser support.
Tone video
The YouTube tone video is rendered from the same data file as the tool, so it plays the same pulses and pauses.
Version history
Version 1 is the only version so far. It has been the tone of the site since the first release. A change to any value above gets a new version number and a changelog entry.