tchrly

Classroom Noise Meter

A live sound level gauge with a too-loud threshold, gentle chime and board mode.

Microphone

Audio is analyzed on this device only. Nothing is recorded or sent anywhere.

Calibration

Measured like a real sound level meter: A-weighted, Fast (125 ms) response, shown in estimated decibels. iPhone and iPad mics run hot, so those start at +20 dB. For any device, one guided calibration below gives the truest reading.

Match a reference meter

Hold a sound level meter (or a phone running a dB app) next to this device while the room stays at a steady level, enter its reading, then measure for 5 seconds.

dB

Start listening first.

Alerts

Threshold crossed 0 times this session.

Board mode look

Theme

Room level

A-weighted with a Fast (125 ms) response, like a real sound level meter. The thin red tick shows the recent peak.

Mic is off

--/100

dB estimate

Start listening to see the room's sound level.

  • Silentunder ~41 dB · Independent work level
  • Whisper~41–53 dB · Quiet partner work
  • Partner talk~53–66 dB · Group work level
  • Getting loud~66–78 dB · Time to bring it down

How to use it

  1. 1Start listening and allow microphone access when the browser asks.
  2. 2The meter works like a real sound level meter: A-weighted with a Fast (125 ms) response.
  3. 3Match a reference meter or phone dB app with the guided calibration, or nudge the offset by hand.
  4. 4Set the too-loud threshold where you want the class warned.
  5. 5Open board mode so students can watch the level themselves and self-regulate.
  6. 6Switch to Bouncing balls for a playful display — balls bounce harder as the room gets louder.

This tool runs entirely in your browser. What you type here is not sent to tchrly or uploaded anywhere.

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