407780 Datasheet, PDF (7/13 Pages) Extech Instruments Corporation. – Integrating Sound Level Datalogger

Sound Pressure Measurements (SPL)
In SPL mode the display shows readings of the sound pressure level.
1. Turn the meter on by pressing the green on/off button.
2. Select the SPL mode by pressing the Leq SEL SPL button until SPL appears on the
LCD.
3. Select the desired Frequency Weighting as needed (A or C).
Change the Frequency Weighting by pressing the A/C button. The 'A' or 'C' icon will
display on the right-hand area of the LCD.
Note: With ‘A’ weighting selected, the meter responds like the human ear. ‘A’
weighting is commonly used for environmental measurements, OSHA regulatory
testing, law enforcement, and workplace design. Select ‘C’ weighting for flat
response measurements. ‘C’ weighting is typically used for the sound level analysis
of machines, engines, etc. Most hearing conservation related testing is performed
using 'A' Weighting.
4. Select the desired Response Time as needed (Fast, Slow or Impulse).
Change the Response Time by pressing the 'FAST/SLOW/IMPULSE' button. The 'FAST'
'SLOW' or IMP icon will display.
Note: Select FAST to capture noise peaks and noises that occur very quickly. In
FAST mode, the meter responds in 125ms. Select the SLOW Mode (meter responds
in 1s) to monitor a sound source that has a reasonably consistent noise level or to
average quickly changing levels. In IMPULSE mode the meter responds in 35ms
and is used to capture sounds such as those produced at a shooting range.
Selection of Fast or Slow is determined by the application and any directives or
standards related to that application. Most hearing conservation related testing is
performed using a SLOW Response Time setting.
5. Hold the instrument comfortably in hand and away from your body or position it on a
tripod. Point the microphone toward the noise source, the sound pressure level will be
displayed on the meter’s LCD display.
MIN/MAX Function
Press the MAX MIN INST button to begin capturing the, Maximum (MAX) OR Minimum
(MIN) sound values. The display will indicate the MAX or MIN value (depending on which is
selected) captured since the MAX/MIN button was pressed. Press and hold the
MAX MIN INST button to return to the instantaneous reading mode
Note:
When the meter is measuring the following buttons cannot be used:
• FAST, SLOW, IMPULSE
• A/C Weighting
• DATE/TIME
• INTEG TIME
• RECORD ERASE
• UP/DOWN Arrow keys
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Model 407780 Version 2.1 09/07