EN 61043:1994
(Main)Electroacoustics - Instruments for the measurement of sound intensity - Measurement with pairs of pressure sensing microphones
Electroacoustics - Instruments for the measurement of sound intensity - Measurement with pairs of pressure sensing microphones
Applies to instruments which detect sound intensity by pairs of spatially separated pressure sensing microphones and specifies performance requirements for instruments used for the measurement of sound intensity, and their associated calibrators. The purpose of this standard is to ensure the accuracy of measurements of sound intensity applied to the determination of sound power in accordance with ISO 9614. To meet the requirements of that standard, instruments are required to analyse the sound intensity in one-third octave or octave bands, and optionally to provide A-weighted band levels.
Elektroakustik - Geräte für die Messung der Schallintensität - Messungen mit Paaren von Druckmikrofonen
Electroacoustique - Instruments pour la mesure de l'intensité acoustique - Mesure au moyen d'une paire de microphones de pression
S'applique uniquement aux instruments qui mesurent l'intensité acoustique au moyen d'une paire de micropones de pression séparés dans l'espace et donne les prescriptions concernant les caractéristiques des instruments utilisés pour la mesure de l'intensité acoustique, ainsi que celles des calibbreurs associés. Le but de cette norme est d'assurer l'exactitude des mesures de l'intensité acoustique, appliquées à la détermination de la puissance acoustique, conformément à l'ISO 9614. Pour satisfaire aux prescriptions de l'ISO 9614, les instruments doivent analyser l'intensité acoustique en bandes d'octaves, ou de tiers d'octaves, et peuvent éventuellement indiquer des niveaux correspondant à la pondération fréquentielle A.
Electroacoustics - Instruments for the measurement of sound intensity - Measurement with pairs of pressure sensing microphones
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2000
Electroacoustics - Instruments for the measurement of sound intensity -
Measurement with pairs of pressure sensing microphones
Electroacoustics - Instruments for the measurement of sound intensity - Measurement
with pairs of pressure sensing microphones
Elektroakustik - Geräte für die Messung der Schallintensität - Messungen mit Paaren von
Druckmikrofonen
Electroacoustique - Instruments pour la mesure de l'intensité acoustique - Mesure au
moyen d'une paire de microphones de pression
Ta slovenski standard je istoveten z: EN 61043:1994
ICS:
17.140.50 Elektroakustika Electroacoustics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
NORME
CEI
INTERNATIONALE IEC
INTERNATIONAL
Première édition
STANDARD
First edition
1993-12
Electroacoustique — Instruments pour la mesure
de l'intensité acoustique — Mesure au moyen
d'une paire de microphones de pression
Electroacoustics — Instruments for the
measurement of sound intensity —
Measurement with pairs of pressure
sensing microphones
© CEI 1993 Droits de reproduction réservés — Copyright — all rights reserved
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1043 ©IEC:1993 — 3 —
CONTENTS
Page
FOREWORD 7
INTRODUCTION 9
Clause
1 Scope 11
2 Normative references 11
Definitions
3 13
4 Grades of accuracy 17
5 Reference environmental conditions 19
6 Sound intensity processors: requirements 19
6.1 Frequency range 19
6.2 Filtering 19
6.3 A-weighting 19
6.4 Indicator accuracy 21
6.5 Provision for microphone separation 21
6.6 Presentation of results 21
6.7 Time averaging 21
6.8 Crest factor handling 23
6.9 Pressure-residual intensity index 23
6.10 Provision for phase compensation 23
6.11 Provision for range setting 23
6.12 Provision for overload indication 25
6.13 Provision for corrections for atmospheric pressure and temperature 25
6.14 Operating environment 25
7 Sound intensity probes: requirements 25
7.1 Mechanical construction 25
7.2 Response to sound pressure 27
7.3 Response to sound intensity 27
7.4 Directional response characteristics 29
7.5 Pe rformance in a standing wave field 31
7.6 Pressure-residual intensity index 31
7.7 Environmental conditions 33
8 Sound intensity instruments: requirements 33
9 Power supplies: requirements 33
1043 ©IEC:1993 – 5
Clause Page
10 Sound intensity probe calibrators: requirements 33
10.1 Sound pressure calibrators 33
10.2 Residual intensity testing devices 33
10.3 Sound intensity calibrators 35
11 Sound intensity processors: performance verification 35
11.1 Octave and one-third octave filters 35
11.2 Sound intensity indication 37
11.3 Time averaging 37
11.4 Crest factor handling 39
11.5 Pressure-residual intensity index and operating range 39
12 Sound intensity probes: performance verification 41
12.1 Frequency response 41
12.2 Directional response 43
12.3 Performance in a standing wave field 43
12.4 Pressure-residual intensity index 43
13 Calibrators: performance verification 45
13.1 Sound pressure calibrators 45
13.2 Residual intensity testing devices 45
13.3 Sound intensity calibrators 45
14 Field calibration and checks 47
15 Marking and instruction manuals 49
15.1 Marking 49
15.2 Instruction manuals 49
Annexes
A Periodic verification procedures 53
B Sound intensity processors employing autoranging 57
C Sound intensity processors based on DFT analysers converting narrow bands
to one-octave or one-third octave 59
D
RC networks for generating known phase shifts 65
E Dynamic capability index 67
1043 ©I EC:1993 - 7 -
INTERNATIONAL ELECTROTECHNICAL COMMISSION
ELECTROACOUSTICS -
INSTRUMENTS FOR THE MEASUREMENT OF SOUND INTENSITY -
MEASUREMENT WITH PAIRS OF PRESSURE SENSING MICROPHONES
FOREWORD
1)
The IEC (International Electrotechnical Commission) is a worldwide organization for standardization
comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to
promote international cooperation on all questions concerning standardization in the electrical and
electronic fields. To this end and in addition to other activities, the IEC publishes International Standards.
Their preparation is entrusted to technical committees; any IEC National Committee interested in
the subject dealt with may participate in this preparatory work. International, governmental and
non-governmental organizations liaising with the IEC also participate in this preparation. The IEC
collaborates closely with the International Organization for Standardization (ISO) in accordance with
conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of the IEC on technical matters, prepared by technical committees on
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
3) They have the form of recommendations for international use published in the form of standards, technical
reports or guides and they are accepted by the National Committees in that sense.
4)
In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
International Standard IEC 1043 has been prepared by IEC technical committee 29:
Electroacoustics.
This standard completes the series of International Standards already prepared or in
preparation by subcommittee 1 of ISO committee 43: Acoustics/noise, ISO/TC 43/SC1.
The text of this standard is based on the following documents:
Six Months' Rule Report on Voting
29(CO)185 29(CO)211
Full information on the voting for the approval of this standard can be found in the repo rt
on voting indicated in the above table.
Annex A forms an integral pa rt of this standard.
Annexes B, C, D and E are for information only.
1043 ©IEC:1993 - 9 -
INTRODUCTION
This International Standard specifies the requirements for sound intensity instruments,
comprising sound intensity probes and processors, which detect sound intensity by pairs
of spatially separated pressure sensing microphones. These instruments, and others
employing different detection methods, are still the subject of development.
Sound intensity instruments have two main applications. The first is the investigation of
the radiation characteristics of sound sources. The second is the determination of the
sound power of sources, especially in situ, where sound intensity measurement enables
sound power determination to be made under acoustical conditions which render determi-
nation by sound pressure measurement impossible.
This International Standard applies to instruments to be used for the determination of
sound power in accordance with the requirements of ISO 9614-1 and ensures well-defined
performance for instruments used in other applications.
Specifications and tolerances are based on current instrument technology and on typical
industrial requirements for dynamic capability index.
Requirements for the verification of pe rformance of probes and processors are written in
terms of type tests. A scheme for periodic verification, serving as the basis of the periodic
recalibrations required in many countries, is given in annex A.
Probes and processors are treated separately and together; in the latter case they are
called "instruments".
1043 ©IEC:1993 -11 -
ELECTROACOUSTICS -
INSTRUMENTS FOR THE MEASUREMENT OF SOUND INTENSITY -
MEASUREMENT WITH PAIRS OF PRESSURE SENSING MICROPHONES
1 Scope
The primary purpose of this Standard is to ensure the accuracy of measurements of sound
intensity applied to the determination of sound power in accordance with ISO 9614-1.
To meet the requirements of that standard, instruments are required to analyse the sound
intensity in one-third octave or octave bands, and optionally to provide A-weighted band
levels. They are also required to measure sound pressure level in addition to sound
intensity level to facilitate the use of the field indicators described in ISO 9614-1.
This International Standard only applies to instruments which detect sound intensity by
pairs of spatially separated pressure sensing microphones.
This International Standard specifies performance requirements for instruments used for
the measurement of sound intensity, and their associated calibrators.
The requirements are intended to reduce to a practical minimum any differences in equi-
valent measurements made using different instruments, including instruments comprising
probes and processors from different manufacturers.
2 Normative references
The following normative documents contain provisions which, through reference in this
text, constitute provisions of this International Standard. At the time of publication, the
editions indicated were valid. All normative documents are subject to revision, and parties
to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the normative documents listed below.
Members of IEC and ISO maintain registers of currently valid International Standards.
ISO 9614-1: 1993,
Acoustics - Determination of sound power levels of noise sources
using sound intensity - Part 1: Measurement at discrete points
IEC 651: 1979, Sound level meters
IEC 942: 1988, Sound calibrators
IEC 1260: 19XX, Specification for octave-band and fractional octave-band filters
(under
consideration). (Revision of IEC 225: 1966)
1043 ©IEC:1993 - 13 -
Definitions
For the purpose of this International Standard, the following definitions apply.
3.1 sound intensity probe:
Transducer system from which signals may be processed
to obtain the sound intensity component in a specific direction.
3.2 p-p probe (also known as a two
microphone probe): Probe composed of two
pressure sensing microphones spaced apart by a fixed and known distance, in which the
sound pressure component is measured by the two microphones and the mean value is
considered as the sound pressure existing at the reference point of the probe, while the
sound pressure differential is used for the purpose of deriving the sound particle velocity
component.
NOTES
1 A side-by-side p-p probe has the two microphones arranged as shown in figuret.
2 A face-to-face p-p probe has the two microphones facing each other and separated by a spacer as
shown in figure 2.
lEC 1232/93
1EC 1231/93
Figure 1 - A side-by-side p-p probe Figure 2 -A face-to-face p-p probe
3.3 reference point of a probe:
Point at which the sound intensity is deemed to be
measured.
NOTE — The reference point of a probe is not necessarily the physical midpoint, but occurs halfway
between the effective microphone centres.
3.4 probe axis: Axis passing through the reference point and along which a component
of particle velocity is sensed.
3.5 reference direction:
Direction of incidence of plane progressive waves on the
probe, parallel to the probe axis, for which the sound intensity response of the probe is
specified.
1043 ©IEC:1993 - 15 -
3.6 phase difference between probe channels for a p-p probe: Difference in phase
response between the channels in a p-p probe, including microphones, preamplifiers and
cables, if they are an integral part of the probe, when subjected to the same input. It is a
function of frequency.
3.7 nominal separation of microphones in a p-p probe: Fixed value of separation
used for the purpose of computing sound intensity directly in an instrument. It is the mean
value of the effective separation of the microphones in a specified frequency range.
3.8 sound intensity processor:
Device whose function is the determination of sound
intensity in conjunction with a specified probe. The processor presents results in one
octave or one-third octave bands, in terms of sound intensity and sound pressure, or
sound intensity level and sound pressure level.
3.9 sound intensity instrument: Comprises a sound intensity probe and a compatible
sound intensity processor.
3.10 residual intensity: False intensity produced by phase differences between
measurement channels, which occurs when the processor is subjected to identical elec-
trical inputs to the two channels, or when the transducers in the probe connected to the
processor are subjected to identical sound pressure inputs.
3.11 pressure-residual intensity index: Difference between the indicated sound
pressure levels and the indicated residual intensity levels, calculated with air density of
1,2048 kg/m3, in one octave or one-third octave bands, when the processor is subjected to
identical electrical pink noise inputs to the two channels, or when the transducers
connected to the inputs are subjected to identical pink noise sound pressure inputs. This
index applies only where
...
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