Larson Davis SoundAdvisor 831C Reference Manual page 155

If Event History is
TAKE NOTE
not enabled, but Event Sound
is, a sound recording is still
made on an exceedance as an
exceedance sound recording.
If a second event is
TAKE NOTE
triggered during a sound
recording, the sound
recording will extend. This
can continue on until there
are no more events. The
sound recording will only be
associated with the first
event, though contain all the
sound for the subsequent
events.
FIGURE 18-9 Sound Event
The record icon will
change from gray to
red during the
snapshot time of the
measurement.
A second sound
TAKE NOTE
recording cannot begin until
the minim duration has
elapsed since the last sound
recording.
The 51.2 sample
TAKE NOTE
rate serves a unique function:
when used with Time History
records, the sound recording
and the time history record
will be synced. At any other
rate, filter delays allow for
decimation so the sound
recordings are not perfectly
synced.
SoundAdvisor Model 831C
Step 5 Save. Select setup, Set to Active. Close.
Step 6 Run a measurement.
Step 7 In this example, when the measured sound is above 65 db
(SPL 1 Trigger Level) for at least 2 seconds (trigger time) it
will record the 11 seconds (pre-trigger + snapshot time) of
the sound.
Constraints
If you indicate the minimum duration and pre-trigger values greater
than the constraint, an error message will appear and the values will
automatically adjust to be within the correct range.
Refer to the following table on the maximum values you can indicate
for the minimum duration (Event History) and pre-trigger (Sound).
Table 18.1 Sound Recording Constraints
Sample Rate
8 ksps
16 ksps
24 ksps
48 ksps
51.2 ksps
Event Sound Recording
Minimum Duration
+
Pre-Trigger ≤
60 s
30 s
20 s
10 s
9.375 s
18-6