Model 407730 Version 1.3 June 2004
4
MAX/MIN Recording
In this mode the meter records the Maximum and Minimum readings and stores them into
memory.
1. Press the
REC
button to enter the RECORD mode. The “REC” icon will appear in the
display.
2. Press the
REC
button again to display the minimum value recorded since the mode was
entered. The “MIN” icon will appear in the display. The meter is not recording during this
time.
3. Press the
REC
button again to display the maximum value recorded since the mode
was entered. The “MAX” icon will appear in the display. The meter is not recording
during this time.
4. Press the
REC
button again to display the present dB level and continue recording.
5. Press and hold the
REC
button until the “REC” icon clears to exit the mode.
Auto-Power Off
The meter will automatically shut off after 20 minutes of operation. To disable this feature:
1. With the meter OFF, Press the and
MAX HOLD
buttons simultaneously.
2. will appear in the display
3. Release the button and then release the
MAX HOLD
button.
4. The meter will remain on until the power button is pressed.
Calibration
To calibrate the meter, an external calibrator such as the Extech 407744 or the Extech
407766 is required in addition to a small screw-driver.
1. Turn the meter ON
2. Select the 80 to 110dB range
3. Select ‘A’ weighting and ‘SLOW’ response
4. Place the microphone into the calibrator. Set the calibrator to output a 1kHz sine wave
@ 94dB
5. Adjust the calibration potentiometer for a display as close as possible to the calibrator’s
output
Battery Replacement
When the low battery icon appear replace the battery by removing the screw securing
the rear battery compartment and replacing the 4 AAA batteries.
Tripod Mount
A camera tripod mount is located on the rear of the meter for increased stability and
elimination of body reflections.
Measurement Considerations
1. Wind blowing across the microphone increases the noise measurement. Use the
supplied windscreen to cover the microphone when applicable.
2. Calibrate the instrument before each use if possible. Especially if the meter has not
been used for a long period of time.
3. Do not store or operate the instrument in areas of high temperature or humidity.
4. Keep meter and microphone dry.
5. Avoid severe vibration.
6. Remove the battery when the meter is to be stored for long periods of time.
