BRUEL & KJAER 2204 - Effects of Vibration and Sound

Effeets of Vibration and Sound.
Fig. 5.8 shows the effect of vibration upon the instrument in terms of the
equivalent sound pressure level and Fig. 5. 7 shows the output from the Sound
Level Meter when exposed to a sound field of approximately 120 dB and with
the microphone replaced by an equivalent sound insensitive capacitor.
dBSPL
90
80
70
60
50
40
12203_ I I I I II I I I I
B
r<c--,
t----+--+-+-+-+-H-++~r""'\+-+ shaker f---+--+-....:... !.&'D-+--+--1--1
=!
I- ~
...
II',
f:J
·"'
:i
::
! ~
N
L:
N
mA~v
,
I
:
. J
I
:
f\
: I \
i 1
::
~
'
I
: {'
! \ l: I~ ,·
' \. ::
t----++-+-+--+-++~r j --+-+-++~IJH ~n H ~
30t-----~4-+4~~~+-~~~~~~~~~~
20 ......__"""t-'-~~ Jo~-U--.a.........L-IJf+.~L.....I-L-I-.I.J.II.~---UI~r~ ~~
10 20 50 100
200
500 1000 2000
5 000
Frequency Hz
167083
Fig. 5.8. The above curves show the effect of vibration upon the Sound Level
Meter.
The instrument is excited in three different directions as shown, and
the acceleration is kept constant at 1 g. The curves marked I are obtained
with the microphone in place, while the curves marked III are obtained with
the microphone replaced by an equivalent sound and vibration insensitive
impedance.
The curves marked II gives the sound pressure developed by the
Shaker measured with another Sound Level Meter Type 2203 (II).
33