Extech Instruments 407780A User Manual page 13

Calibration
Calibrating the Integrating Sound Level Datalogger requires an acoustical calibrator such as the
Extech Model 407766 or 407744.
1. Configure the meter as follows:
• Display: SPL (dBA)
• Time weighting mode: FAST
2. Insert the microphone into the opening of the acoustical calibrator.
3. Switch the calibrator ON.
4. Adjust the meter's calibration potentiometer as shown in the
accompanying diagram until the meter's display matches the
acoustical calibrator output signal (typically 94 or 114dB).
5. Switch the calibrator OFF.
6. Remove the calibrator from the microphone very slowly to avoid
damaging the microphone.
7. In cases where adjusting the potentiometer does not affect the
displayed reading, or where the adjustment cannot produce the
appropriate displayed reading, please return the unit for service.
800.561.8187
13
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