Classroom noise meter

Set up the display before the activity begins, while the room is quiet. Choose a limit that fits the task: quiet reading and small-group discussion may need different settings.

1. Press Turn on microphone, then grant microphone access when your browser asks.
2. With the room quiet, press Calibrate quiet. The tool listens for 3 seconds to set the quiet baseline.
3. Use View to choose Bar, Traffic light, or Bouncing balls.
4. Adjust Noise limit to suit the activity. The default is 70 on the relative scale from 0 to 100; higher Sensitivity makes the display react to quieter sounds.
5. Press Full screen to show only the tool on your projector or smartboard.
6. When the activity ends, press Turn off microphone. Leaving the page also stops the microphone.

No. The level from 0 to 100 is relative to the room’s quiet baseline and your microphone, not a calibrated measurement in decibels. Use it as a classroom visual cue, not as a measurement of sound exposure.

The traffic light is green below your limit minus 15, amber from that point up to the limit, and red above it. The too-loud warning requires 1.5 seconds above the limit, then clears after 1 second below it, so a single clap or dropped book does not trigger the warning.

If the display reacts to quiet sounds more than you want, lower Sensitivity. Use Calibrate quiet again when you want to reset the quiet baseline for the room.

In Chrome, grant access when the microphone prompt appears. If you previously blocked it, open the browser settings, find site permissions under privacy and security, then open microphone permissions and change this page’s permission to allow access.

In Safari on a Mac, open the browser settings and go to the website-specific settings. Select microphone permissions, then use the menu beside this page to allow access or require a permission prompt.

In Edge or Firefox, press Turn on microphone and grant access when the browser asks. Permission is required before the page can use your microphone; the browser also displays an indicator while it is in use.

Microphone access requires a secure connection. On a school-managed Chrome browser, your administrator may control microphone permissions, so you may need help from your school’s technology staff.

Explain what the display means before turning it toward your class. Set the limit for the activity rather than treating every task as silent work.

• Independent reading: show the traffic light while students read, and turn off the microphone when the reading block ends.
• Small-group work: keep the bar visible during discussion and agree on a limit that allows conversation.
• Centers: use the bouncing balls during the work period as a shared visual reference for room volume.
• Quiet writing: display the meter from the start of the writing task until you bring the class back together.