Larson Davis System 824, Technical Reference Manual

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9/29/09 Overview 2-5
The following parameters can be logged at user-selectable
time intervals between 1 second and 99 hours (hh:mm:ss)
• L
max
, L
min
, SEL, and L
eq
(q=3) or Time Weighted Aver-
age (q=4, 5, or 6) levels for a selected detector (Slow,
Fast, or Impulse) and a selected frequency weighting (A,
C, or Flat)
• L
peak
level corresponding to the frequency weighting
selected for L
eq
(see charts above) and a second L
peak
level corresponding to one of the two alternative choices
of frequency weighting.
• L
n
(6 values with 0.1 dB resolution, based on user-
selected percentages with 0.01% resolution)
• Date, time and duration of interval
• Six user-selected values of L
n
can be measured and
stored as part of the automatic interval data storage func-
tion.
• A special feature is the automatic measurement and log-
ging of data associated with noise exceedance events that
are triggered by the sound level exceeding a user-defined
threshold. L
eq
, SEL and L
Peak
for each event are logged
along with a Time History of the sound level during each
event.
• Daily history and community noise metrics.