
17
Reference
The output sound pressure level
L
(dB) is expressed by equation 2.
Output sound pressure level
L
(dB) = 10 × log
10
p
2
p
0
2
............................... Equation 2
p
0
: Reference sound pressure 2 × 10
-5
Pa
The output sound pressure level
L
(dB) with compensation for static (atmospheric) pres-
sure is expressed by equation 3.
Output sound pressure level
L
(dB) =
L
s
+ 20 × log
10
P
a
P
o
....................... Equation 3
P
a
: Static pressure at time of use
kPa
P
o
: Reference static pressure
101.325 kPa (reference conditions)
L
s
: Specifi ed sound pressure level for microphone in use
dB