Larson Davis 831, User Manual

Page: 424 / 548

Model 831 Manual Sound Exposure Metrics Measured 24-3
Live Tab
From the Live tab, the graphic shows the instantaneous SPL
value for all frequencies and the bar to the far right shows
the summation value for the entire frequency band. The
value corresponding to the cursor position is displayed
numerically beneath the graph.
Overall Tab
From the Overall tab, the graphic shows the energy
equivalent level calculated over the measurement time
period at each frequency band and, at the far right, for the
summation of all frequency bands. The values displayed
digitally beneath the graph represent the following data for
the frequency band at the cursor position.
• Leq
• Lmax
• Lmin
Sound Exposure Metrics Measured
See Chapter 9 “Industrial Hygiene”
on page 9-1 The Model 831 measures two separate and independent sets
of sound exposure metrics.
The following parameters are user-selectable:
• Exchange Rate: 3, 4, 5 or 6 dB
• Threshold Enable: Yes or No
• Threshold Level: Numeric entry
• Criterion, Level and Hours: Numeric entries
In Table 24-2: "Sound Exposure Metrics Measured" the
symbol X is used to represent the user-selected RMS and
Impulse frequency weighting (A, C or Z) and the symbol Y
is used to represent the user-selected peak frequency
weighting (A, C or Z).