SPL(sound pressure level) meter app uses your phone mic to measure noise volume in decibels(db), and shows a reference. We had calibrated many android devices with the actual sound level meter with dB(A).

REMEMBER!! The smart phone microphones were aligned to human voice (300-3400Hz, 40-60dB). Therefore the maximum values are LIMITED by the manufacturers. The very loud sound cannot be recognized. Moto Droid(max.100), Galaxy S(81dB), Galaxy S2(98dB)...

Vibrometer app uses your built-in sensors to measure phone's vibration or the earthquake, and shows a reference.

The measured values are the Modified Mercalli Intensity scale(MMI). If it is inaccurate, you can calibrate it so that the maximum value is about 10-11.

* Pro version added Features:- Sound Meter and Vibrometer are integrated- Statistic menu and Save log data- Level notification- Line-chart duration- More models are calibrated- No ads

* Do you want more tools?Get [Smart Tools] package.

For more information, see the manual, Youtube video and the blog. Thank you.

** Not Compatible with: Xperia(X8, X10 mini), LG(Optimus One, P350), GT-I9001, ZTE, etc