This application measures ambient noise in decibel using the built in microphone of the iPhone and the external measuring microphone i436. It features a reference view showing typical noise producers in relation to the currently measured noise. It can record up to 12 hours of samples, which are stored on iCloud in CSV files for further analytics.
Disclaimer:
Even though the dBMeter Pro Software has been calibrated using professional grade equipment, do no use dBMeter Pro to carry out professional measurements. The author can not be held liable for any damage which might arise by using dBMeter Pro.