407732 Datasheet, PDF (6/6 Pages) Extech Instruments Corporation. – Digital Sound Level Meter

Calibration
To calibrate the 407732, an external calibrator such as the Extech 407744 or the Extech
407766 is required in addition to a small screw-driver.
1. Open the battery compartment and locate the two
calibration potentiometers behind the 9V battery (see
diagram)
2. Turn the meter ON
3. Put the meter in the ‘A’ weighting mode
4. Put the meter in the ‘SLOW’ response mode
5. Place the 407732 microphone into the calibrator. Set
the calibrator to output a 1kHz sine wave @ 94dB
6. Put the meter in the low range
7. Adjust the ‘A (Lo)’ potentiometer for a display of 94.0
dB
8. Put the meter in the high range
9. Adjust the ‘A (HI)’ potentiometer for a display of 94.0
dB
Battery Replacement
When the low battery icon BAT appears on the LCD replace the 9V battery as soon as
possible. The battery compartment cover is located on the rear of the meter. Remove the
Phillips screw to loosen the cover. Slide the battery compartment cover off, change the
battery, and replace the compartment cover.
Typical A-Weighted Sound Levels
50HP Siren (100')
Jet takeoff (200')
Riveting machine
Subway (20')
Pneumatic drill (50')
Vacuum cleaner (10')
Large store
Small office
Night residential area
Whisper (5'0)
Threshold of hearing
dBA
140
130
120
110
100 Chain saw
90 _{Boiler room}
80 _{Freight train (100')}
70 _{Speech (1')}
60 _{Large Office}
50 _Residence
40
30
20 ^{Sound studio}
10
0
Copyright © 2004 Extech Instruments Corporation
All rights reserved including the right of reproduction in whole or in part in any form.
6
Model 407732 Version 1.4 June 2004