onllm.dev 
Sound Meter
A decibel meter that tells you what the number means.
Coming to Google Play
Sound Meter is finished and awaiting Google Play review. This page will link straight to the store listing as soon as it is live.
What it does
- Live loudness in dBA with a plain-language label such as “Normal conversation” or “Heavy traffic”, and how long that level is safe for, following WHO and NIOSH exposure guidance.
- A colour-coded gauge — green, amber above 85 dB, red above 95 dB — with a peak-hold mark for the loudest level so far.
- A-weighted by default, matching how the ear hears and how hearing-safety limits are defined. Switch to Z (unweighted) for machinery and low rumble.
- Octave-band spectrum from 63 Hz to 8 kHz, so you can see whether the noise is rumble, voices or hiss.
- History over the last 30 seconds, 5 minutes or 30 minutes. Touch the graph to read the level at any moment.
- Sessions. Record a room, a machine, a journey or a night out at one reading per second. Each session keeps its own graph, duration, average, peak and time above 85 dB, and can be renamed or shared as a CSV.
- Loud alert. Pick a threshold between 80 and 100 dB; the card flashes and the phone vibrates once when the sound goes above it.
- Widget and quick settings tile showing the last level you measured. Neither ever listens on its own.
- Reference list of everyday sounds from a whisper to a siren, with typical dB and daily exposure limits.
Honest about accuracy
Phone microphones are not calibrated instruments. They are tuned for speech, they roll off at the extremes of the frequency range, and they compress loud sounds. Readings from this app are estimates — usually within about 5 dB — and must not be used for workplace compliance or any legal purpose.
If you have access to a meter you trust, “Match a reference meter” in Settings lets you stand the phone beside it, type in what that meter reads, and have Sound Meter match it. That takes a multi-second average rather than an instantaneous value, so the correction is stable.
About the microphone
The microphone is used only while the meter screen is open and in front of you. Audio is analysed in memory to compute a number and is never recorded, stored or transmitted. A recorded session holds decibel figures only — no audio, no speech. The app has no internet permission, so it could not upload anything even if it tried.
What it does not do
- No advertisements, no analytics, no trackers.
- No internet access, and no permission other than the microphone.
- No audio is recorded, stored or sent. Read the privacy policy.
Support
Email contact@onllm.dev. Please include your phone model and Android version.