User manual

113
Noise Curves
11
Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor follows automatically the frequency
band with the highest noise rating.
Select the frequency with the rotary wheel •
.
Press enter •
.
You may read out any individual frequency.•
Return to auto frequency with enter •
.
 The cursor returns to the frequency with high-
est noise rating.
The cursor readout may be set manually to any
frequency band or wide band level. The readout re-
mains at the selected frequency.
Select the frequency with the rotary wheel •
.
Press enter •
.
Select the frequency of interest.•
Confirm with enter •
.
 The cursor readout
2
displays the measure-
ment results of the selected frequency band.
12
SIL Measurement Result
The speech interference level (SIL) result is shown for
noise curve types NC-2008 and NC-1995
1
. It is calcu-
lated by averaging the octave-band sound pressure levels
at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. If the measured
spectrum in any octave band does not exceed any of the
octave bands of that NC(SIL) curve, the spectrum is des-
ignated NC(SIL). If one or more octave-band levels exceed
the NC(SIL) curve, then the NC curve number may differ to
the SIL value, as the NC rating for that spectrum must be
determined using the tangency method.
13
Large Fluctuations
This reports any large fluctuations at low frequencies
for the Room Noise Criteria RNC in accordance with
ANSI S12.2-2008. If one or more displayed measurement
results exceed the limits, then large fluctuations exist. Con-
cluding the LEQ levels in the octave frequency bands be-
low 300 Hz are automatically “penalized” at the RNC mea-
surement.
14
Correction Values
The noise curve type RNC uses these correction values
based on the measured fluctuation results to determine
the RNC curve result.