Larson Davis SoundTrack LxT, User Manual

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C
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24 Glossary and Formulas LxT Manual
SEL Calculations
The LxT 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:
Alternatively, SEL can also be calculated with this formula:
All of the SEL energy values in the sound level meter 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.
SEL 10 Log
10
p
2
t
 
t d
T
1
T
2

p
0
2
T
-------------------------
=
SEL k 10
L
s
 
k
--------
s 1 =
n









32
 
log – log

=