All instruments need to be field checked/calibrated to verify the sound levels.
Mount the sound calibrator on the microphone and turn it on. Push the CAL button, select the input channel and enter the Calibration menu. A special calibration display with a spectrum part and a calibration history for the actual transducer is shown. Use right and left cursor buttons to select the calibration frequency (e.g. 1 kHz for a standard calibrator) or a network (C usually works fine). If the level is OK you can select to exit the calibration menu now, but we reccomend that you do one of the following check procedures.
The history graph shows the historical calibration values for this transducer. There may be a red line in this diagram indicating calibration results obtained in a calibration laboratory, while the blue line represents all the field checks or calibrations that are performed by the operator.
Tap the "Manual" selection. The sensitivity can now be adjusted up and down.
Use the orange + and - buttons at the bottom of the screen until the expected dB level is obtained. The step size is dependant on the number of decimals selected for the dB numbers (0 - 3, See Setup Instrument Menu).
Set the calibrator frequency and level before you press the orange Calibrate! button. The instrument will then start an automatic procedure to calculate the correct correction. When finished, the new sound level and correction are displayed and when you accept the new values are stored with the sensor.
Typical Norsonic Sound Calibrators
Please be aware that something may be wrong either with the transducer or with its settings if it is a need to change the sensitivity with more than a few tenths of a dB.