Larson Davis SoundAdvisor 831C, Reference Manual

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SoundAdvisor Model 831C Making an Automated Event Sound Recording 18-4
Step 4
Save the Setup, set it as the Active setup file, and Close (
/*/
) the Setup
Manager.
Step 5
Run a measurement and examine the resulting sound recordings. Based on the
settings shown in Figure 18-3 , when the measured sound is above 65 dB ( SPL 1
Trigger Level
) for at least 4 seconds (
Trigger Time
) the event recording would
include 11 seconds of sound (Pre-t Snapshot Time).
FIGURE 18-4
Sound Event Live Example
1.
If you monitor the measurement, notice that the record icon
changes from gray to red during the designated Snapshot Time.
TAKE NOTE
If a second event (such as a measurement history or
manually triggered sound recording) begins during an ongoing
sound recording, the sound recording extends. This continues
until there are no more events. When you examine the recording
after the measurement, you will find that the sound recording is
associated to the first event even though it contains sound
recordings for the subsequent events.
18.3.1 About Sound Recording Constraints
Because of sound buffering demands, there are constraints on the values you
can set for the
Minimum Duration
and
Pre-trigger
. If the values you enter
require more buffer than is available, an error message appears and the
values automatically adjust to accommodate the recording.
Table 18.1 displays the maximum values you can indicate for the
Minimum
Duration (Event History) and Pre-trigger (Sound) when using automated
Event Sound Recording.
TAKE NOTE
The 51.2 ksps sample rate serves a unique function— when used with Time
History records, the sound recording and the Time History record are synced.
At any other sample rate, filter delays prevent this time synchronization.
1.
Table 18.1 Sound Recording Constraints
Sample Rate
Minimum Duration
+
Pre-Trigger ≤
8 ksps 60 s
16 ksps 30 s
24 ksps 20 s
48 ksps 10 s
51.2 ksps 9.375 s