Decibel

Decibel is a sound level meter. It opens measuring: no start button, no
settings to visit first.

• The level in dB, with the word that goes with it: Calm, Busy, Loud, Harmful
over time
• Minimum, maximum, average and peak since you last started again
• The last minute drawn under the number, with the 85 dB line always visible:
a room is judged by its noise over a while, not at an instant
• Fast and Slow, the two time weightings of real meters (125 ms and 1 s)
• The average is the energy average (Leq), not the average of the decibels: a
slammed door cannot be cancelled out by averaging it with silence
• Above 85 dB the phone buzzes and the screen turns red — that is the level
where prolonged exposure damages hearing

One thing said plainly: **it is an estimate**. A phone microphone is not a
calibrated instrument, and no app can make it one. If you have a real meter you
can compare and move the calibration: from then on the scale is yours.

What Decibel does not do:
• no account, no sign-up
• **it does not record**: the sound is analysed in the phone's memory and
thrown away, and no file is ever written
• no location, no servers of ours

Permissions: microphone (to hear the room), Internet (ads only) and vibration.
The app is free and paid for by ads: a banner at the bottom, away from the
controls, and an occasional full-screen ad only after a finished measurement.

Privacy policy:
https://mindcontact.app/mcma-decibel/privacy/