Larson Davis 831 - APPENDIX C Integrated Level Calculations; Equivalent Continuous Sound Level

Model 831 Manual Integrated Level Calculations C-1
APPENDIX
C
Integrated Level Calculations
Basic Integrated Level Calculations
Equivalent Continuous Sound Level
The Larson Davis Model 831 calculates equivalent
continuous sound levels based on equations from IEC
standard 61672-1, Section 3.9 which defines L
eq
as follows:
Note that the 831 displays the equiv-
alent continuous A-weighted sound
pressure level as L
Aeq
.
Equivalent continuous A-weighted sound pressure level
(also average A-weighted sound pressure level) is defined as
follows:
where:
L
AeqT
is the equivalent continuous A-weighted sound
pressure level re 20 µPa, determined over a time interval T
 is a dummy variable of time integration over the averaging
time interval ending at the time of observation t
T is the averaging time interval
p
A
() is the A-weighted sound pressure
p
0
is the reference sound pressure of 20 µPa
In the equation, the numerator of the argument of the
logarithm is the root-mean-square, frequency-weighted
sound pressure level over the averaging time interval T.


dBPdP
T
LL
Tt
A



















0
2/1
2
AeqTAT
/
1
lg20

