Model 90 Quantifier Sound Level Meter
Page 62
Calibrating a Sound Level Meter.
Push the microphone of the Sound Level Meter into the cavity at the end of the
calibrator. Ensure the microphone is fully inserted into the cavity and is past the ‘O’ ring
seals. The microphone should be parallel to the body of the calibrator. Also ensure that
the small bleed-hole next to the microphone cavity is not blocked as this could cause
damage to the microphone.
Most modern Sound Level Meters have electronic calibration with the level adjusted
automatically. Adjust the Sound Level Meter to the correct level where applicable.
When correcting the value generated by the calibrator a correction for the type of
microphone capsule may need to be applied (see Appendix 2)
Background Noise
In order for the calibrator to operate as intended, the ambient acoustic noise level
should be no greater than 80dBA.
Stabilisation
In order for the sound pressure level and frequency to stabilise after switching the
calibrator on when coupled to a microphone, a period of at least 3 seconds should be
allowed before performing a calibration.
