Let the room see its own volume
Telling a class to be quieter works for about thirty seconds. Showing them works longer: a needle on the board that rises when the room gets loud and a line that marks how loud is too loud turn an argument into a target everyone can see.
This page listens through the device's microphone and turns the sound into a level from 0 to 100, many times a second. Choose an activity — silent work, whispering, group work, free time — or set your own limit. When the room stays above it, the screen turns red; when it is calm, calm time keeps adding up, which many teachers use as a class goal.
Nothing is recorded. The sound becomes a single number inside the browser and is thrown away; no audio is stored and nothing is sent to a server.
Using it in a lesson
Calibrate in the room you teach in: every microphone and room sounds a little different.
Put the page on the board and press “Start listening”. The browser asks once for permission to use the microphone.
Pick an activity, or press “Set limit from the room now” while the class is at the volume you want; the limit goes a little above it.
Teach as usual. Over the limit for more than a moment, the screen turns red and, if you like, chimes; the counters show calm time and how often the limit was crossed.
What the meter does
Simple on purpose: a class should read it at a glance.
- A needle gauge with green, amber and red zones
- Four activity presets and a limit you can set yourself
- A short delay, so a dropped book or one laugh is not a warning
- A red screen and an optional chime when the room stays too loud
- Calm time and a count of warnings, with a reset button
- A sensitivity setting for quiet microphones or large rooms
- Full screen for the projector
- No recording: only a number is calculated, in the browser
Lessons, libraries and quiet spaces
Wherever volume is part of the instructions.
A year-3 teacher runs silent reading with the limit set low and promises five minutes of free time for every twenty calm minutes.
A secondary science class uses the group work preset so pairs can talk while the class as a whole stays under the line.
A school library shows the meter on a wall screen during exam season.
A teaching assistant uses it in the dinner hall to show children when the noise is climbing.
A home-schooling parent uses whisper mode during a sibling's video lesson.
An open-plan office team puts it on a monitor during focus hours.
How loud is “loud”?
The level is relative, not a calibrated sound measurement. A very quiet room on a typical laptop microphone sits near 0, normal talking lands in the middle, and shouting reaches the top. The presets — 35, 50, 65 and 80 — are starting points; use “Set limit from the room” or the slider to fit your room and device.
The room has to stay over the limit for a moment before it counts, so a single bang does not trigger a warning. To turn calm again, the level has to drop clearly under the limit for about a second, which stops the screen from flickering when the class sits right at the line.
What it is not
It is not a sound level meter for health, safety or noise regulations, and the numbers are not decibels. Use a certified meter for anything official.
Readings depend on the device: a laptop on the teacher's desk hears the front of the room better than the back.
It needs microphone permission and works only while the page is open. Some browsers pause audio processing in a background tab, so keep it on screen.
For a meter the class respects
- Set the limit with the class: ask them to work at the right volume for a minute, then press “Set limit from the room now”.
- Reward calm time rather than punishing warnings; the counter makes the goal concrete.
- Keep the chime off in silent work: the red screen alone is enough and does not add noise.
- Put the device where it hears the whole room, not next to the noisiest table.
Noise meter questions
Does it record my class?
No. The microphone signal is converted into a single loudness number in the browser and discarded. No audio is saved and nothing leaves the device.
Are the numbers decibels?
No. The 0–100 scale is relative to what the microphone can hear. It is good for comparing a room with itself, not for official measurements.
Why does it not react to a single loud noise?
On purpose. The room has to stay over the limit for a moment, so a dropped pencil case or one laugh does not count as a warning.
What limit should I choose?
Start with a preset — silent work, whisper, group work or free time — then fine-tune with the slider or set the limit from the room's current volume.
The needle barely moves. What can I do?
Raise the sensitivity, move the device closer to the class, or check that the browser is using the right microphone.
It says the microphone is blocked.
Allow the microphone for this site in the browser's address bar or settings, then press Start listening again.
Does it keep working in another tab?
Not reliably. Some browsers pause audio processing in background tabs. Keep the page on screen, ideally in full screen.