24
Reference
3. When effective load volume of microphone is known
1-inch microphone
Output sound pressure level
L
(dB)
=
L
0
+ (-0.00041 × (
V
L
- 960)) + 20 × log
10
P
a
101.325
1/2-inch or 1/4-inch microphone
Output sound pressure level
L
(dB)
=
L
0
+ (-0.00041 × (
V
L
+
V
A
- 960)) + 20 × log
10
P
a
101.325
L
0
: Specifi ed sound pressure level at reference conditions (as per calibration chart, dB)
P
a
: Static pressure at time of use (kPa)
V
L
: Effective load volume of microphone in use (mm
3
)
V
A
: Effective load volume with 1/2-inch adapter or 1/4-inch adapter
Load volume with 1/2-inch adapter: 909 mm
3
Load volume with 1/4-inch adapter: 832 mm
3
Effective load volume of microphone at reference conditions:
960 mm
3
Static pressure used for reference:
101.325 kPa
Output sound pressure level change according to microphone effective load volume:
-0.00041 dB/mm
3