Sound Meter Pro is part 4 of Smart Tools (noise, vibrations, Seismometer) package.
The level of sound (SPL) meter uses the phone microphone to measure the noise level in decibels (dB) showing a reference. We have calibrated much android devices with a measuring actual sound level in dB (A).
REMEMBER!! The majority of buses are aligned for the human voice (300-64kbit), so the maximum values are limited by the manufacturers. A stronger sound can not be measured. Moto Droid (max.100), Galaxy S3 (81dB), Galaxy S2 (98dB)…
The Vibrometer application uses the sensors integrated in the phone to measure the vibrations of the phone or an earthquake, showing a reference.
The measured values are governed by intensity of Modified Mercalli (MMI) scale. If the measurement is not accurate, you can calibrate it yourself in a way that the maximum value is about 10-11.
In the Pro version
-Sound Meter and Vibrometer included
-Statistics menu and save historical data
-Duration of the line graph
-More calibrated models