SoundAdvisor Model 831C
Understanding the Overall Tab
4-10
The normalized octave band page displays the numerical values of the
highlighted band. The data is then normalized using the Spectral Ln value you
select in the measurement setup file.
If the frequency components are too small or too large, use the Adjust Graph
function described in
.
FIGURE 4-14
Overall Tab: 1/3 Octave Spectral Ln
1.
Ln as a function of frequency for the 6 user-selected
values of
n
.
2.
Ln values at highlighted band.
3.
Frequency at highlighted band.
4.2.6 About the Ln Percentiles Page (Overall Page)
FIGURE 4-15
An Ln percentile is a statistical measurement of the level that
exceeds the selected value “n” percent of the time. The
statistics are based on the level defined by the current
weighting and detector.
The Ln Percentiles page displays the 6 Ln statistics for the
measurement based on the run time, and the maximum and
minimum sound levels measured. You can customize the
threshold level in the measurement setup prior to or during a
measurement. For details on this, see
Values On the Setup Manager Tabs
LEARN MORE
For a more in-depth discussion of Ln values, see
“
Ln Value
”
.
1.
L
NF50
= 60.8 dB
means that the Fast (F) time-weighted level
exceeded 60.8 dB 50% of the time during the measurement.
Table 4.3 Reference Spectra Options
User Defined
1 2 3 4
Positive Frequency Weighting
A C
Negative Frequency Weighting
-A -C
1.
3.
2.
1.
