Larson Davis SoundAdvisor 831C Reference Manual page 25

Table 2.4 OBA Overload Levels
Input Gain, dB
OBA Under Range Icon
Measurement Status
SoundAdvisor Model 831C
When the OBA Range property is set to Low, the OBA Overload Icon will
activate at a level 33 dB lower than it would had the OBA Range been
set to Normal.
When using a microphone having a sensitivity of 50 mV/Pa, the input
overload will occur approximately as shown in Table 2.4.
0
20
0
20
When the signal from the preamplifier drops to the point where the
noise level of the instrument and the preamplifier influence the
measurement, an under range condition exists.
When all filters of the OBA are "under range" the OBA Under Range Icon
appears.
FIGURE 2-15
As long as this under range condition exists, the icon will flash. When
the measured OBA levels no longer produces an under range condition,
the icon will be removed from the display.
The state the meter is currently in will be indicated by a measurement
status icon. The measurement status is indicated by five icons for the
five states: run, stop, reset, pause, run pending.
Displays and Icons
OBA Range
Normal
Normal
Low
Low
OBA Under Range Icon
Overload Level, dB
143
123
110
90
2-11