This application can be used to measure ambient noise in Decibels. Even though dBMeter Pro is pretty much self-explanatory there are a few things that you should know:
iPhone measurement and calibration in the lab
Explanation of the controls
Use the Impulse mode to measure fast fluctuating noise. The 128ms mode averages the values over a period of 128 milliseconds, while the 1s mode does average over 1 second. These time intervals are internationally standardized for noise measuring equipment.
Toggles between the A-weighted and C-Weighted mode. A-weighting is the most commonly used of a family of curves defined in the International standard IEC 61672:2003 and various national standards relating to the measurement of sound pressure level. A-weighting is applied to instrument-measured sound levels in effort to account for the relative loudness perceived by the human ear, as the ear is less sensitive to low audio frequencies. It is employed by arithmetically adding a table of values, listed by octave or third-octave bands, to the measured sound pressure levels in dB. The resulting octave band measurements are usually added (logarithmic method) to provide a single A-weighted value describing the sound; the units are written as dB(A). The C-weighting approximates the sensitivity of human hearing at industrial noise levels (above about 85 dBA). The C-weighted sound level (i.e., measured with the C-weighting) is more sensitive to sounds at low frequencies than the A-weighted sound level and is sometimes used to assess the low-frequency content of complex sound environments. The linear mode does not apply any weighting and treats every frequency equally.
The iPhone and iPod are able to measure environmental noise with up to 120 dB(A). Use this switch to toggle the sensitivity of dBMeter Pro. LO is suitable for most measurements in normal environments with 20 up to 90 dB(A). Use the HI setting in loud environments with 40, up to 120 dB(A). Note: being exposed to noise above 85 dB(A) for a long period of time may cause hearing problems. Always wear noise protection gear!
Starts recording samples. Recording can be stopped at any time by pressing the “Stop” button
This button is only enabled when the dBMeter is recording sample. When touched recording will be stopped.
This button is only enabled after recording. Touching this button will display the recorded values in a landcape graph. Turning the iPhone back from Landscape to Portrait mode will hide the graphics.
This button is only enabled after recording. Touching this button sends the recorded samples in comma separated format (CSV) to the eMail application and stops dBMeter Pro. The eMail application will open up and the samples can be sent via eMail for further analysis.
Even though the dBMeter Pro Software has been calibrated using professional grade equipment (B&K 2215), do no use dBMeter Pro to carry out professional measurements. The author can’t be held liable for any damage which might arise by using dBMeter Pro.
go to Dr. Edwin Schorer at Mueller BBM GmbH for measuring the characteristics of the iPhones and calculating the calibration values.
iPhone and iPod touch are trademarks of Apple Inc. Alle rights reserved.