Acoustic Calibrators for Sound Level Meters
Acoustic Calibrators are used to set the sensitivity of the microphone of the sound level meter for field work (the SLM should be recalibrated annually to a traceable national standard). It is recommended, just as with air sampling pumps, that calibration should be made before and after a series of measurements.
Class 2 Calibrators produce a tone at a single frequency (typically 1 kHz) at a specified Sound Pressure Level (SPL).
Class 1 Calibrators produce a tone at the same frequency but at two different SPL’s. Class 1 Calibrators must be corrected for barometric pressure, as stated in IEC 60942:2003, using a barometer and a conversion table, and this is supplied with the Class 1 Calibrator. If required the barometer can be purchased separately, to be used with a Class 2 Calibrator.