Larson Davis System 824, Technical Reference Manual

Page: 614 / 673

D-18 824 Reference Manual 9/29/09
Sound Exposure (SE)
It is the total sound energy of the actual sound during a
specific time period. It is expressed in Pascals-squared
seconds.
where p
A
is the sound pressure and T
2
- T
1
is the
Measurement Duration (specific time period).
When applied to hearing damage potential, the equation is
changed to
where k is the Exposure Factor. See Exchange Rate.
Standard : ANSI S1.25
Sound Exposure Level (SEL,
L
ET
)
The total sound energy in a specific time period. The
equation for it is
The sound pressure is squared and integrated over a specific
period of time (T
2
-T
1
) this is called the sound exposure and
has the units Pascal squared- seconds or Pascal squared-
hours. P0 is the reference pressure of 20 µPa and T is the
reference time of 1 second. It is then put into logarithmic
SE p
A
2
t
( )
t d
T
1
T
2
∫
=
SE p
A
2
t
( ) [ ]
k
t d
T
1
T
2
∫
=
SEL 10 Log
10
p
2
t
( )
t d
T
1
T
2
∫
p
0
2
T
-------------------------
=