Measuring

NIOSH tested 192 phone sound meter apps and four met the accuracy criterion of ±2 dB(A) against a type 1 reference. With external calibrated microphones those four reached ±1 dB. Android accuracy cannot currently be verified because the hardware ecosystem is fragmented.

When acoustic measurement is part of a wider workplace review, this resource can add operational context, but it should not be treated as a substitute for calibrated sound data.

Calibration is what anchors a reading to reality. Without it, an instrument reports a number with no established relationship to the physical quantity — and phones fail here specifically because their microphones have automatic gain control.

Meter classes are permitted-error specifications, not quality grades, and a type 1 instrument out of calibration is worse than a calibrated type 2.

For standards, background, or a second perspective, consult Larson Davis sound and vibration basics.

A meter measures a place and a dosimeter measures a person. Area measurement finds where the problem is; dosimetry finds who has it.

For additional technical context, see HearingTracker.

Measuring a room properly takes twenty minutes and a procedure: calibrate before and after, measure at ear height where people are, average over a representative period, and record the settings.

Audio software reports a different quantity entirely — dBFS relative to digital full scale, with no fixed relationship to sound pressure.

And a recording proves a sound occurred rather than how loud it was, which is frequently exactly what a complaint needs.