DIN EN ISO 3743-2-2009 声学.声压法测定噪声源声功率级.混响声场中小型可移动声源的工程检测法.第2部分:专用混响试验室法(ISO 3743-2:1994),EN ISO 3的德文版本
Acoustics - Determination of sound power levels of noise sources using sound pressure - Engineering methods for small, movable sources in reverberant fields - Part 2: Methods for special reverberation test rooms (ISO 3743-2:1994); English version of DIN E
1.1 General
This part of ISO 3743 specifies a relatively simple en-
gineering method for determining the sound power
levels of small, movable noise sources. The
measurements are carried out when the source is in-
stalled in a specially designed room having a specified
reverberation time over the frequency range of
interest. The A-weighted sound power level of the
source under test is determined from a single A-
weighted sound pressure level measurement at each
microphone position, rather than from a summation
of octave-band levels. This direct method eliminates
the need for a reference sound source, but requires
the use of a special reverberation test room. The di-
rect method is based on the premise that the sound
pressure level, averaged in space and time in the test
room, can be used to determine the sound power
level emitted by the source. The properties of the
special reverberation test room are chosen so that the
room's influence on the sound power output of the
equipment under test is small. The number of micro-
phone positions and source locations required in the
test room are specified. Guidelines for the design of
special reverberation rooms are given in annex B.
in addition to the direct method, a comparison
method is also described (see 8.3). However, since
the requirements on the test room for the comparison
method of ISO 3743-1 are considerably less restric-
tive, it is recommended that the comparison method
of ISO 3743-1 be used if a special reverberation test
room is not available.
NOTE 1 Precision methods for the determination of the
sound power levels of small noise sources are specified in
ISO 3741 and ISO 3745.
1.2 Types of noise
The methods specified in this part of ISO 3743 are
suitable for measurements of all types of noise within
a specified frequency range, except impulsive noise
consisting of isolated bursts of sound energy.
NOTES
2 A classification of different types of noise is given in ISO 12001.
3 For sources of impulsive noise consisting of short-
duration noise bursts, the free-field methods specified in
ISO 3744 and ISO 3745 should be used.