How to use it
- Press Start test.
- When the browser asks, choose Allow.
- Speak at a normal volume. The bar follows your voice and the orange mark shows the loudest moment so far.
- Press Stop when you are done. This turns the microphone off completely.
What the meter shows
The page connects the microphone to the browser’s audio analyser and, on every screen frame, takes the root-mean-square (RMS) of the current sound wave. That value is drawn as the bar. The decibel figure is 20 × log10 of the same value.
Frames are only drawn while the test is running, and stopping it releases the audio stream, so a stopped test uses no resources.
Worked example
If the RMS level is 0.1, the reading is 20 × log10(0.1) = −20 dB, and the bar is about 32 % full because the bar uses a square-root scale that makes quiet sounds easier to see. A level of 0.01 gives −40 dB.
Troubleshooting
- Blocked permission. Click the icon next to the address bar, set the microphone to Allow and press Start again.
- Several microphones. The browser uses its default input; change it in the browser’s site settings or your system sound settings.
- Other apps. On some systems a video call app can keep the microphone busy. Close it and retry.