Measurement Preparation - Extech Instruments 407790 User Manual

Calibration
Use a standard acoustic calibrator such as the Extech 407744 or
407766. Acoustic calibration if often performed on a daily basis to
compensate for any possible changes in microphone sensitivity.
1. Configure the following switch settings.
Display: SLM (L
Time weighting: FAST
2. Insert the microphone carefully into the insertion hole of the
calibrator.
3. Turn on the calibrator and adjust its CAL potentiometer so
that the display matches the calibrator output.
4. Note that the 407790 is fully calibrated before shipment.
5. Recommended full recalibration cycle: 1 year.

Measurement Preparation

1. Battery loading: Remove the rear battery cover and insert four 1.5V 'C' size batteries.
Take care to observe battery polarity.
2. Battery replacement: When the battery voltage drops below operating voltage,
3. LBATT flashes on the display.
4. AC adaptor connection: Insert the adaptor in the DC 6V jack on the side panel.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX 781.665.0780 - TestEquipmentDepot.com
FAST
L
A
dB
100
90
80
70
60
50
40
30
Hz 31.5 125
[ 1 / 3 OCT ] 01 / 07/ 27 14:26:39
)
A
W 75.2 dB
500 2k 8k L W