Larson Davis 831, User Manual

Page: 226 / 548

Model 831 Manual Trigger Method 13-5
To select the Level Trigger Method, highlight the Trigger
Method field and press
5
to open the Trigger Method
menu, shown inFIGURE 13-3.
FIGURE 13-3 Trigger Method Menu
Highlight Level and press
5
to implement the selection.
Dynamic Trigger Method
Dynamic triggering is a technique in which event triggering
tracks the background level. This is implemented by making
the event trigger levels equal to the background level plus an
offset. The following example illustrates the value of this
feature.
Barking Dog Example
During the day the sound of a barking dog may be masked
by background noises such as passing cars, lawn mowers,
etc. whereas during the night, when the background noise is
lower, this would more likely be perceived as an annoyance.
Fixed Level Trigger
When performing unattended noise monitoring on a 24-hour
basis using a fixed trigger level which is appropriate for
capturing the higher level events, the dog barks would be
missed since they are below the trigger level, as shown in
FIGURE 13-4.