Norsonic nor118, Инструкция по эксплуатации

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64 Chapter 11
About sound power measurements
65 Norsonic Nor118
User Guide
Sound power –
acoustic environment
requirements
A
test area outdoors or an ordinary room will provide
a suitable environment, if the requirements given in
the   of the   and briefly outlined here, are
satisfied.
Reflecting objects other than reflective plane(s) shall
be removed to the extent possible from the vicinity of
the machine under test. A test site shall ideally provide a
measurement surface which lies
a
inside a sound field that is essentially undisturbed by
reflections from nearby objects and the room bounda-
ries, and
b
outside the near field of the sound source under test.
α Description of Room
0.05 Nearly empty room, smooth hard walls made
concrete, brick, plaster or tile
0.1 Partly empty room, room with smooth walls
0.15 Room with furniture, rectangular machinery or
industrial room
0.2 Irregularly shaped room with furniture, irregu-
larly shaped machinery or industrial room
0.25 Room with upholstered furniture, machinery or
industrial room with small amount of acoustical
material
0.35 Room with acoustical material on both ceilings
and walls
0.5 Room with large amounts of acoustical material
on ceiling and wall
When measuring in accordance with the ISO 3746, the envi-
ronmental correction factor K
2
is obtained from this graph by
entering the abscissa with the appropriate value of A/S
10
9
8
7
6
5
4
3
2
1
0
0.5 1 5 10 50 100
300
A/S
dB
K
2
= 10log
10
[1+ 4]
A/S