Understanding Level And Dynamic Triggering - Larson Davis SoundAdvisor 831C Reference Manual

17.5 Understanding Level and Dynamic Triggering

17.5.1 Understanding Level Triggering
FIGURE 17-8
Event History with Level Triggering
1.
SoundAdvisor Model 831C
ALL
•
When you select ALL, the meter triggers an event when all of the OBA values
exceed the Reference Spectra selected for the Full Octave.
• ANY
When you select ANY, the meter triggers an event when at least one of the OBA
values exceeds the Reference Spectra selected for the Full Octave.
• Spectrum from the Third Octave drop-down menu
• ALL (as described above, but for the Third Octave Spectra)
• ANY (as described above, but for the Third Octave Spectra)
Step 6.
Return to Step 5 of 17.1 "Setting Up the Event History Measurement" on page
126 to complete the Setup.
Your 831C SLM provides 2 ways to calculate an event trigger. The event trigger using Level
Triggering is the static value you set. With dynamic triggering, the event trigger level
adjusts according to the background noise (and any indicated offset) in each time history
period.
In this section:
• 17.5.1 Understanding Level Triggering
• 17.5.2 Understanding Dynamic Triggering
Using this method, all triggers are determined directly by their set threshold level, which is
static throughout the entire measurement. The threshold level is calculated using all
measured sound.
1.
The yellow line indicates the event trigger level, which was set at 84dB. The Leq in this
example ran for a 24 hour period using a 1 second Time History Period.
Understanding Level and Dynamic Triggering 134