Division 2.3 Calibration of the entire Acoustic Measurement System for measurement session

At the beginning and at the end of every measurement session, the entire acoustic measurement system shall be checked by means of a sound calibrator that complies with the requirements for sound calibrators of precision class 1 as set out in IEC 60942: 2003. Without any further adjustment the difference between the readings shall be less than or equal to 0,5 dB. If that value is exceeded, the results of the measurements obtained after the previous satisfactory check shall be discarded.