You can measure the environmental noise in decibels. Sound Level Meter is the part 4. of Smart Tools series. (noise) Acoustimeter uses your phone mic to measure noise volumn in decibels(dB) and shows a reference. SPL(sound pressure level) noisemeter. REMEMBER!! The most of the microphone has been aligned to human voice(300-3400Hz) and not required high performance. So the hardware maximum values are LIMITED. (See the sound pressure at calibrate menu. it stops at 32767.)

• See the 4nd image. Moto Droid(Max.100), Galaxy S(Max.81), Galaxy S2(98dB), Galaxy Tab, Desire and Desire HD have been calibrated by the real sound level meter dB(A).
• Pro version added features 1) No ads 2) Vibrometer Pro is included 3) Statistic menu 4) Level notification 5) Line-chart duration 6) More models are calibrated