12
Chapter 4
Technical description
Self-noise and wind
The figure below shows typical self-noise for the mi-
crophone system as levels for the various 1/3-octave
frequency bands re. 20 µPa when the microphone is
placed in a horizontal, laminar flow of air with speed 0,
5 and 10 m/s, respectively. The levels are measured
without frequency compensation. The correspond-
ing A-weighted levels are 16 dB, 40 dB and 48 dB.
Depending on the wind speed, the noise levels are
typically 20 dB to 30 dB lower than for an unprotected
microphone.
0
10
20
30
40
50
60
70
80
90
6,
3
8
10
12
,5
16
20
25
31
,5
40
50
63
80
10
0
12
5
16
0
20
0
25
0
31
5
40
0
50
0
63
0
80
0
1
k
1.
25
k
1.
6
k
2
k
2.
5
k
3.
15
k
4
k
5
k
6.
3
k
8.
3
k
10
k
12
.5
k
16
k
20
k
So
un
d
pr
es
su
re
l
ev
el
[d
B]
1/3 octave frequency band [Hz]
0 m/s
5 m/s
10 m/s
Summary of Contents for nor1218
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