BRUEL & KJAER 2209 - Sound

Fig.5.11.
Change in microphone sensitivity with ambient air pressure
.
'"'00000000000000000000000000000000000
35
dB
po
25
t20
15
10
5
0
10
.........
..
12
50
150
- 250
mmHg 350
450
550
650
mmHg 752
.........
Fig. 5. 12. Microphone frequency response with varying air pressure
vanat1on from normal atmospheric pressure to 10% produces a change in
microphone sensitivity
of± 0.2 dB.
5.7. SOUND
A typical graph of the acoustic sensitivity of the meter without micro-
phone is shown in Fig.5.13. This shows the sensitivity for the linear position
59