Sound Meter: Decibel & Noise

A sound meter that shows the noise around you in decibels, and keeps out of the way while it does.

■ Nothing covers the reading
There is a banner at the bottom and nothing else. No full-screen ad opens while you are measuring, and the ad that usually appears when an app comes to the front is held back until you stop.

■ The level now, and the average, max and min
The sound pressure level (SPL) in dB as it changes, with the average, maximum and minimum since you started. A word comes with the number, so it means something: Moderate (normal conversation), Very loud (inside a train).

■ A-weighting
The A-weighting curve from IEC 61672, which follows how human ears hear. You can switch it off and read the sound flat.

■ Frequency
Ten octave bands from 31 Hz to 16 kHz under the meter, so you can tell a low rumble from a high whine.

■ Record and save
Measure for 1, 5, 10, 30 or 60 minutes, or until you stop. The result - average, maximum, minimum and a graph of the whole run - is saved to your gallery as one image with the date and time on it.

■ Calibration
Phone microphones differ. If you have a meter you trust, nudge the reading in 0.5 dB steps until the two agree. The app remembers it.

■ The last 60 seconds
A graph under the number shows how the noise level has moved, so a short bang is still there to look at after it has gone.

Good for
・Noise from a neighbor, a road or an air conditioner
・How loud a shop, a classroom or a workshop is
・Checking a speaker or a car audio system
・Watching the level while a machine runs
・Checking that headphones or an instrument are not too loud

About the numbers
A phone microphone has a noise floor of about 30 dB and cannot read much above 100 dB. The app asks for the microphone and nothing else, and the sound itself is never recorded or sent anywhere. Treat the readings as a guide: this is not a certified sound level meter.