Classroom noise monitor
Project this page on the board and let the meter show the room how loud it is. It runs in the browser, needs no install or account, and no audio is recorded or sent anywhere.
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dB SPL (est.)
Meter stopped
0306090130 dB
- Minimum
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- Average
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- Maximum
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- Duration
- 0s
Audio never leaves your device — nothing is recorded or uploaded.
Calibration (match a reference meter)
Browsers expose microphone signal level, not absolute sound pressure, so a fixed offset converts the measured signal into an estimated dB SPL value. If you have a calibrated sound level meter or a reference source, adjust the offset until the readings agree. The offset is stored in this browser only.
Target levels for classroom activities
| Activity | Workable level |
|---|---|
| Silent reading or tests | Under 40 dB |
| Partner work, whisper voices | 40–55 dB |
| Group work, table talk | 55–65 dB |
| Presentations and discussion | 60–70 dB |
Acoustic standards for classrooms (ANSI S12.60) recommend background noise below 35 dBA in unoccupied rooms so speech stays intelligible. Occupied rooms sit higher; the bands above are practical working targets, not standards.
Tips for using it well
- Place the device away from a projector fan or air vent, which add several decibels.
- Agree the target band with the class before the activity starts, not after.
- Use Reset stats between activities so the average reflects the current task.
- Keep the tab in the foreground — browsers throttle background tabs.