ODDOOOOODOOOOOOODOODDODDDDODDODOOODOOO[
Bruel
&
KiaH
BruE
100
:10
d
50
OP
0102
830088
Fig. 4.3.
Example
of
recording
with
"F"
(Fast)
time
weighting
ODDOODODDDDOOOOOOOODODDDOOODDDDOOOODDO[
Bruel
& Kjoor
100
Brue
10
dB
50
OP
0102
830086
Fig. 4.4.
Example
of
recording
with
"/"
(Impulse)
time
weighting
formed
with
the same overall accuracy. However, because
of
its
ease
of
calibration
AC
recording is generally preferred.
To
be able
to
determine
the
reverberation
time
from
a
recording,
AC recording with the "Reverb."
time
weighting
on the 2317 should be used.
4.1.1. DC Recording Calibration
The
control
settings
and
corresponding
pen
deflection
for
calibration
of
the 2317 Level
Recorder
with
different
reference sources (with
or
without
the
20
dB
attenuator
of
the
Sound Level
Meter
fitted) are given in Fig.4.5. Before
proceeding
to
calibrate
the Sound
Level
Meter
and Level Recorder
combination
the
preliminary
checks
described
in
their
Instruction
Manuals should be
carried
out.
Example: With a FSD "80" selected on the Sound Level
Meter,
and a COARSE SENSI-
TIVITY
"1
V" selected on the Level Recorder, the
recording
span will be 20
to
70 dB.
To
increase the
calibration
accuracy, the "Reduced" PEN SPEED
may
be used
during
the
calibration
procedure.
Remember
to return
to
"Normal"
PEN SPEED
before
proceeding
to
record measurements.
23
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