Larson Davis 831, User Manual

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C-4 Basic Integrated Level Calculations Model 831 Manual
n is the total number of samples taken in the measurement.
The sample rate is 32 samples per second.
L
cal
is the calibration offset that corrects for various
sensitivities of microphones
SEL Calculations
Note that the 831 displays SEL as
L
XE
, where X is the frequency
weighting ( X = A, C or Z ).
SEL is available for the overall measurement and is
calculated using this formula:
All of the SEL energy values in the analyzer utilize the
Threshold and Exchange Rate settings. Care should be taken
when modifying these settings since some standards or
governments require SEL to be taken without a Threshold
(set it to zero) and with an Exchange Rate of 3dB.
FIGURE C-2 Sound Exposure Level and Sound Exposure
SEL L
cal
k 10
L
s
 
k
--------
s 1 =
n









32
 
log – log

+ =
Sound Exposure Level
Sound Exposure in hours
Sound Exposure in seconds