Norsonic NOR150, Instruction Manual

Page: 102 / 216

86 Chapter 20
Building Acoustic
When the pre-set measurement duration is ended,
or the
Stop
key is pushed the display changes its
appearance. The frequency bar graph of the fi rst view
changes to a line graph. If measured beforehand,
a black line will indicate the average level of the
previously measured background noise. Figures 20.34
and 20.35.
It is a good idea to save your work frequently. We
advise you to store your measurement project each
time you have accepted a measurement. Activate
the ‘Auto Save On Accept’ option in the Memory
setup and the system will to take care of this task
for you
Making the Background noise
measurements
Set the measurement type to Background noise
(Tip: use the
FUNC
key). Push either the large
START/STOP
key or the
Start
soft key to run the
measurement. The display will then show the frequency
spectrum of the receiving room in the same way as for
the level measurements (Figure 20.36). Each graphical
view has an associated numerical table available. Just
push the
TBL
button to access it.
The background noise
measurements must be
accepted or cancelled in
the same way as the level
measurements.
Additional background noise
measurement positions may
now be measured by a new
click on the
Start
key.
Figure 20.34 - Single
channel view with Bgn Figure 20.35 - Dual
channel view with Bgn
Figure 20.36
The bottom menu now presents
√
and keys for
the acceptance or cancellation of this performed
measurement.
Upon accepting the measurement, these values are
taken into account and put into the calculation of the
average level. Cancellation of the measurement will
discard the values and the average values remains
unchanged.