Electroacoustics - Sound level meters - Part 3: Periodic tests

IEC 61672-3:2013 describes procedures for periodic testing of time-weighting, integrating-averaging, and integrating sound level meters that were designed to conform to the class 1 or class 2 specifications of the second edition of IEC 61672-1. The aim of the standard is to ensure that periodic testing is performed in a consistent manner by all laboratories. The purpose of periodic testing is to assure the user that the performance of a sound level meter conforms to the applicable specifications of IEC 61672-1 for a limited set of key tests and for the environmental conditions under which the tests were performed. Periodic tests described in this edition of IEC 61672-3 apply to sound level meters for which the manufacturer claims conformance to the specifications of the second edition of IEC 61672-1. Periodic tests described in IEC 61672-3 apply to sound level meters for which the model has been, or has not been, pattern approved by an independent testing organization responsible for pattern approvals in accordance with the test procedures of the second edition of IEC61672-2. This second edition cancels and replaces the first edition published in 2006. This second edition constitutes a technical revision. The main changes with regard to the previous concern conformance to specifications which is now demonstrated when measured deviations from design goals do not exceed the applicable acceptance limits, and when the uncertainty of measurement does not exceed the corresponding maximum-permitted uncertainty, with both uncertainties determined for a coverage probability of 95 %. In this document, references to IEC 61672-1, IEC 61672-2, and IEC 61672-3 refer to the second editions unless stated otherwise. Procedures for the periodic testing of sound level meters designed to conform to the specifications of IEC 61672-1:2002 were given in IEC 61672-3:2006.

Elektroakustik - Schallpegelmesser - Teil 3: Periodische Einzelprüfung

Electroacoustique - Sonomètres - Partie 3: Essais périodiques

La CEI 61672-3:2013 décrit les procédures relatives aux essais périodiques des sonomètres à pondération temporelle, des sonomètres intégrateurs-moyenneurs et des sonomètres intégrateurs conçus pour répondre aux spécifications de la classe 1 ou de la classe 2 de la CEI 61672-1. L'objet de la présente norme est de s'assurer que les essais périodiques sont effectués de manière cohérente par tous les laboratoires. Le but des essais périodiques est d'assurer à l'utilisateur que les performances d'un sonomètre répondent aux spécifications applicables de la CEI 61672-1, pour un nombre limité d'essais clé et pour les conditions d'environnement dans lesquelles ces essais ont été réalisés. Les essais périodiques décrits dans la CEI 61672-3 s'appliquent aussi aux sonomètres pour lesquels la conformité aux spécifications de la deuxième édition de la IEC 61672-1 a été déclarée par le fabricant. Les essais périodiques décrits dans la CEI 61672-3 s'appliquent aux sonomètres dont le modèle a été ou n'a pas été approuvé par un organisme d'essai indépendant, responsable des approbations de modèles conformément aux procédures d'essai de la deuxième édition de la CEI 61672-2. Cette deuxième édition annule et remplace la première édition parue en 2006. Cette deuxième édition constitue une révision technique. Les modifications techniques majeures suivantes par rapport à l'édition précédente concernent la conformité aux spécifications qui est maintenant démontrée lorsque les écarts mesurés par rapport aux valeurs nominales ne dépassent pas les limites d'acceptation applicables, et lorsque l'incertitude de mesure ne dépasse pas l'incertitude maximale autorisée correspondante, les deux incertitudes étant déterminées pour une probabilité de couverture de 95 %. Dans le présent document, les références aux CEI 61672-1, CEI 61672-2, et CEI 61672-3 s'entendent pour les deuxièmes éditions, sauf indication contraire. Les procédures pour réaliser les essais périodiques de sonomètres conçus pour être conformes aux spécifications de la CEI 61672-1:2002 ont été données dans la CEI 61672-3:2006.

Elektroakustika - Merilniki zvočne jakosti - 3. del: Redno preskušanje (IEC 61672-3:2013)

General Information

Status
Published
Publication Date
12-Dec-2013
Technical Committee
Drafting Committee
Current Stage
6060 - Document made available
Due Date
13-Dec-2013
Completion Date
13-Dec-2013

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Elektroakustik - Schallpegelmesser - Teil 3: Periodische EinzelprüfungElectroacoustique - Sonomètres - Partie 3: Essais périodiquesElectroacoustics - Sound level meters - Part 3: Periodic tests17.140.50ElektroakustikaElectroacousticsICS:Ta slovenski standard je istoveten z:EN 61672-3:2013SIST EN 61672-3:2014en01-marec-2014SIST EN 61672-3:2014SLOVENSKI

STANDARDSIST EN 61672-3:20081DGRPHãþD
SIST EN 61672-3:2014
EUROPEAN STANDARD EN 61672-3 NORME EUROPÉENNE
EUROPÄISCHE NORM December 2013

CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung

CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2013 CENELEC -

All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 61672-3:2013 E
ICS 17.140.50 Supersedes EN 61672-3:2006
English version
Electroacoustics -
Sound level meters -
Part 3: Periodic tests (IEC 61672-3:2013)
Electroacoustique -
Sonomètres -
Partie 3: Essais périodiques (CEI 61672-3:2013)
Elektroakustik -
Schallpegelmesser -
Teil 3: Periodische Einzelprüfung (IEC 61672-3:2013)

This European Standard was approved by CENELEC on 2013-11-04. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

SIST EN 61672-3:2014

EN 61672-3:2013 - 2 - Foreword The text of document 29/814/FDIS, future edition 2 of IEC 61672-3, prepared by IEC/TC 29 "Electroacoustics" in cooperation with the International Organization of Legal Metrology (OIML), was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 61672-3:2013. The following dates are fixed: – latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2014-08-04 – latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2016-11-04

This document supersedes EN 61672-3:2003. EN 61672-3:2013 includes the following significant technical changes with respect to EN 61672-3:2003. In this second edition, conformance to specifications is demonstrated when a) measured deviations from design goals do not exceed the applicable acceptance limits, and

b) the uncertainty of measurement does not exceed the corresponding maximum-permitted uncertainty, with both uncertainties determined for a coverage probability of 95 %. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 61672-3:2013 was approved by CENELEC as a European Standard without any modification. SIST EN 61672-3:2014

- 3 - EN 61672-3:2013 Annex ZA (normative)

Normative references to international publications with their corresponding European publications The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

NOTE

When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.

Publication Year Title EN/HD Year IEC 60942 - Electroacoustics - Sound calibrators EN 60942 - IEC 61094-5 - Measurement microphones

Part 5: Methods for pressure calibration of working standard microphones by comparison EN 61094-5 - IEC 61094-6 - Measurement microphones

Part 6: Electrostatic actuators for determination of frequency response EN 61094-6 - IEC 61183 - Electroacoustics - Random-incidence and diffuse-field calibration of sound level meters EN 61183 - IEC 61672-1 - Electroacoustics - Sound level meters

Part 1: Specifications EN 61672-1 - IEC 61672-2 - Electroacoustics - Sound level meters

Part 2: Pattern evaluation tests EN 61672-2 - IEC 62585 - Electroacoustics - Methods to determine corrections to obtain the free-field response of a sound level meter EN 62585 - ISO/IEC Guide 98-3 - Uncertainty of measurement

Part 3: Guide to the expression of uncertainty in measurement (GUM:1995) - - ISO/IEC Guide 99 - International vocabulary of metrology - Basic and general concepts and associated terms (VIM) - -

SIST EN 61672-3:2014
SIST EN 61672-3:2014

IEC 61672-3 Edition 2.0 2013-09 INTERNATIONAL STANDARD NORME INTERNATIONALE Electroacoustics – Sound level meters –

Part 3: Periodic tests
Electroacoustique – Sonomètres –
Partie 3: Essais périodiques

INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE R ICS 17.140.50 PRICE CODE CODE PRIX ISBN 978-2-8322-1078-9

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale ®

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé. SIST EN 61672-3:2014

– 2 – 61672-3

IEC:2013 CONTENTS FOREWORD ........................................................................................................................... 3 1 Scope ............................................................................................................................... 5 2 Normative references ........................................................................................................ 5 3 Submission for testing ...................................................................................................... 6 4 Conformance .................................................................................................................... 6 5 Preliminary inspection ....................................................................................................... 7 6 Power supply .................................................................................................................... 7 7 Environmental conditions .................................................................................................. 8 8 General test requirements ................................................................................................. 8 9 Sound calibrator ............................................................................................................... 8 9.1 General ................................................................................................................... 8 9.2 Information for operation .......................................................................................... 9 9.3 Information for testing .............................................................................................. 9 9.4 Calibration of the sound calibrator ............................................................................ 9 10 Indication at the calibration check frequency ..................................................................... 9 11 Self-generated noise ......................................................................................................... 9 11.1 Microphone installed ................................................................................................ 9 11.2 Microphone replaced by the electrical input-signal device ....................................... 10 12 Acoustical signal tests of a frequency weighting .............................................................. 10 13 Electrical signal tests of frequency weightings ................................................................. 12 14 Frequency and time weightings at 1 kHz ......................................................................... 13 15 Long-term stability .......................................................................................................... 14 16 Level linearity on the reference level range...................................................................... 14 17 Level linearity including the level range control ................................................................ 14 18 Toneburst response ........................................................................................................ 15 19 C-weighted peak sound level .......................................................................................... 16 20 Overload indication ......................................................................................................... 16 21 High-level stability ........................................................................................................... 17 22 Documentation ............................................................................................................... 17

SIST EN 61672-3:2014
61672-3
IEC:2013 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
ELECTROACOUSTICS –
SOUND LEVEL METERS –
Part 3: Periodic tests

FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). 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. 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 IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61672-3 has been prepared by IEC technical committee 29: Electroacoustics, in cooperation with the International Organization of Legal Metrology (OIML).

This second edition cancels and replaces the first edition published in 2006. This second edition constitutes a technical revision.

The main technical changes with regard to the previous edition are as follows: In this second edition, conformance to specifications is demonstrated when:

a) measured deviations from design goals do not exceed the applicable acceptance limits, and

b) the uncertainty of measurement does not exceed the corresponding maximum-permitted uncertainty, with both uncertainties determined for a coverage probability of 95 %. SIST EN 61672-3:2014

– 4 – 61672-3

IEC:2013 The text of this second edition is based on that of the first edition and the following documents: FDIS Report on voting 29/814/FDIS 29/825/RVD

Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts in the IEC 61672 series, published under the general title Electroacoustics – Sound level meters, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication will be

• reconfirmed, • withdrawn, • replaced by a revised edition, or • amended. A list of all parts of the IEC 61672 series, published under the general title Electroacoustics – Sound level meters, can be found on the IEC website.

SIST EN 61672-3:2014
61672-3
IEC:2013 – 5 –
ELECTROACOUSTICS –
SOUND LEVEL METERS –
Part 3: Periodic tests

1 Scope This second edition of IEC 61672-3 describes procedures for periodic testing of time-weighting, integrating-averaging, and integrating sound level meters that were designed to conform to the class 1 or class 2 specifications of the second edition of IEC 61672-1. The aim of the standard is to ensure that periodic testing is performed in a consistent manner by all laboratories.

NOTE 1 In this document, references to IEC 61672-1, IEC 61672-2, and IEC 61672-3 refer to the second editions unless stated otherwise.

NOTE 2 Procedures for the periodic testing of sound level meters designed to conform to the specifications of IEC 61672-1:2002 were given in IEC 61672-3:2006.

The purpose of periodic testing is to assure the user that the performance of a sound level meter conforms to the applicable specifications of IEC 61672-1 for a limited set of key tests and for the environmental conditions under which the tests were performed.

The extent of the tests in this part of IEC 61672 is deliberately restricted to the minimum considered necessary for periodic tests.

Periodic tests described in this edition of IEC 61672-3 apply to sound level meters for which the manufacturer claims conformance to the specifications of the second edition of IEC 61672-1. Periodic tests described in this part of IEC 61672 apply to sound level meters for which the model has been, or has not been, pattern approved by an independent testing organization responsible for pattern approvals in accordance with the test procedures of the second edition of IEC 61672-2.

Because of the limited extent of the periodic tests, if evidence of pattern approval is not publicly available, no general conclusion about conformance to the specifications of IEC 61672-1 can be made, even if the results of the periodic tests conform to all applicable requirements of this edition of IEC 61672-3. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60942, Electroacoustics – Sound calibrators IEC 61094-5, Measurement microphones – Part 5: Methods for pressure calibration of working standard microphones by comparison IEC 61094-6, Measurement microphones – Part 6: Electrostatic actuators for determination of frequency response IEC 61183, Electroacoustics – Random-incidence and diffuse-field calibration of sound level meters SIST EN 61672-3:2014

– 6 – 61672-3

IEC:2013 IEC 61672-1, Electroacoustics – Sound level meters – Part 1: Specifications IEC 61672-2, Electroacoustics – Sound level meters – Part 2: Pattern evaluation tests IEC 62585, Electroacoustics – Methods to determine corrections to obtain the free-field response of a sound level meter ISO/IEC Guide 98-3, Uncertainty of measurement – Part 3: Guide to the expression of uncertainty in measurement (GUM:1995) ISO/IEC Guide 99, International vocabulary of metrology – Basic and general concepts and associated terms (VIM) 3 Submission for testing 3.1 An instruction manual applicable to the model and version of the sound level meter shall be available in order to perform periodic tests of a sound level meter. If an applicable Instruction Manual is not submitted along with the sound level meter, nor available at the laboratory, nor publicly accessible from the Internet web site of the manufacturer or supplier of the sound level meter, then no periodic tests shall be performed. 3.2 The source for the instruction manual shall be described in the documentation for the periodic tests.

3.3 All items or accessories for the sound level meter that are necessary for periodic testing shall accompany the sound level meter when it is submitted for testing. A device specified in the instruction manual for inserting electrical signals equivalent to signals from the microphone shall also be submitted if requested by the laboratory. 3.4 Periodic tests as described in this part of IEC 61672 shall not be performed unless the markings on the sound level meter are as required by IEC 61672-1 or there is evidence that the sound level meter was originally so marked. The serial number and the model designation shall be visible on the sound level meter. 3.5 Data required to perform the periodic tests shall be available and the source of the data shall be recorded and reported by the laboratory. The data shall include all relevant information required by IEC 61672-1 and IEC 62585. 3.6 A sound calibrator shall be available. The sound calibrator shall be supplied with the sound level meter, if required by the user or if requested by the laboratory, or shall be supplied by the laboratory. If a suitable sound calibrator is supplied by the user, it shall be used by the laboratory to establish the acoustical sensitivity of the sound level meter. 4 Conformance 4.1 Conformance to a performance specification is demonstrated when the following criteria are both satisfied: (a) a measured deviation from a design goal does not exceed the applicable acceptance limit and (b) the corresponding uncertainty of measurement does not exceed the corresponding maximum-permitted uncertainty of measurement given in IEC 61672-1 for the same coverage probability of 95 %. IEC 61672-1 gives example assessments of conformance using these criteria. 4.2 For laboratories performing periodic tests, the uncertainties associated with all measurements shall be determined in accordance with the procedures of ISO/IEC Guide 98-3. Metrological terms shall be as defined in ISO/IEC Guide 99. Actual measurement uncertainties shall be calculated for a coverage probability of 95 %. Calculation of the uncertainty of SIST EN 61672-3:2014

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IEC:2013 – 7 –

measurement for a particular test should consider at least the following components, as applicable. Other uncertainty components are noted in Clauses 7, 12, and 13. – The uncertainty attributed to calibration of the individual instruments and equipment used to perform the test, including the sound calibrator and any free-field facility; – The uncertainty resulting from environmental effects or adjustments; – The uncertainty resulting from small errors that may be present in the applied signals; – The uncertainty attributed to effects associated with the repeatability of the results of the measurements. When a laboratory is only required to make a single measurement, it is necessary for the laboratory to make an estimate of the contribution of random effects to the total uncertainty. The estimate should be determined from an evaluation of several measurement results previously obtained for a similar sound level meter; – The uncertainty associated with the resolution of the display device of the sound level meter under test. For digital display devices that indicate signal levels with a resolution of 0,1 dB, the uncertainty component should be taken as a rectangular distribution with semi-range of 0,05 dB; – The uncertainty associated with the device used to mount the sound level meter in the free-field test facility; – The uncertainty resulting from the deviation of the sound field in the free-field test facility from an ideal free sound field; and – The uncertainty associated with each correction applied to the measurement data. 4.3 If an actual uncertainty of measurement for a test performed by the laboratory exceeds the corresponding maximum-permitted uncertainty, the result of the test shall not be used to evaluate conformance to this part of IEC 61672 for periodic testing.

4.4 A laboratory’s actual uncertainty, without inclusion of the uncertainty of the manufacturer’s free-field or random-incidence correction data, shall not exceed the corresponding maximum-permitted uncertainty from IEC 61672-1. However, when the uncertainty of the manufacturer’s correction data is included it is possible that an actual uncertainty of measurement may exceed the corresponding maximum-permitted uncertainty only because the uncertainty of the manufacturer’s correction data was a significant part of the laboratory’s uncertainty budget. In this event, testing may proceed, but the documentation for the periodic tests shall include a statement to explain the reasons that the results of a test did not conform to a specification of IEC 61672-1.

5 Preliminary inspection Prior to any measurements, the sound level meter and all accessories shall be visually inspected, paying particular attention to damage to, or accumulation of foreign material on, the protection grid or diaphragm of the microphone. All relevant controls shall be operated to ensure that they are in working order. If the controls, display, and other essential elements are not in proper working order, no periodic tests shall be performed.

6 Power supply For all tests, the sound level meter shall be powered from its preferred supply or a suitable alternative. Before and after conducting the set of tests with acoustical signals and before and after conducting the set of tests with electrical signals, the power supply for the sound level meter shall be checked by the method stated in the Instruction Manual to ensure that it is within the specified operating limits. If the voltage or the equivalent indication of the status of the power supply is not within the operating limits and the reason cannot be attributed to partially discharged batteries or an incorrect selection of the voltage of the public power supply, then no periodic tests shall be performed as a malfunction is indicated.

SIST EN 61672-3:2014
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IEC:2013 NOTE Changes to the output of the power supply can be determined as changes to the percentage of the voltage from fully-charged batteries, or by an equivalent procedure.

7 Environmental conditions 7.1 Periodic tests shall be performed within the following ranges of environmental conditions: 80 kPa to 105 kPa for static air pressure, 20 °C to 26 °C for air temperature, and 25 % to 70 % for relative humidity.

7.2 As a minimum, the static air pressure, air temperature, and relative humidity shall be measured and recorded at the start and end of periodic testing.

7.3 Unless data are available for the influence on the model of a sound level meter of the deviations in the prevailing environmental conditions from the reference environmental conditions, for periodic tests of frequency weightings conducted at a static pressure less than 97 kPa, the laboratory shall assign a standard uncertainty of 0,09 dB for measurements at frequencies less than or equal to 3 kHz and a standard uncertainty of 0,14 dB for measurements at frequencies greater than 3 kHz.

NOTE The two standard uncertainties are for use when values for the standard uncertainties are not available from the potential sources listed in 12.6. The two values were determined from estimates of 0,15 dB and 0,25 dB respectively for the maximum influence of static pressure on frequency response for models of microphones that have the greatest air stiffness in the back cavity. 8 General test requirements 8.1 Periodic tests described in subsequent clauses apply only for those design features that are required by IEC 61672-1 and that are available in the sound level meter submitted for test. All such features shall be tested.

8.2 For all periodic tests, the configuration of the sound level meter shall be as requested by the user and shall be as specified in the Instruction Manual for one of the normal modes of operation, including all required accessories. For a sound level meter that provides selectable settings for corrections to the relative frequency response for the influence of any accessories or for other configurations of the sound level meter, the tests shall be performed using the settings that are appropriate for the configuration of the sound level meter in its normal mode of operation. Any such settings shall remain unchanged throughout the testing. 8.3 Electrical signals shall be inserted into the sound level meter through the input device or by the means specified in the Instruction Manual. The deviation of the frequency of an input signal from a specified frequency shall not exceed 0,25 % of the specified frequency.

8.4 For a sound level meter that has an electrical output that is to be used for periodic tests, the indications obtained from the electrical output and the corresponding indications on the display device of the sound level meter shall be confirmed to be identical within the acceptance limits given in IEC 61672-1. Where multiple outputs are present, if an output is specified in the Instruction Manual for testing, that output shall be used for periodic testing.

8.5 The laboratory shall use instruments that have been calibrated for the appropriate quantities at appropriate intervals. As required, the calibrations shall be traceable to national standards.

9 Sound calibrator 9.1 General The sound calibrator shall preferably be a model specified in the Instruction Manual for use with the sound level meter, or alternatively a sound calibrator producing the same nominal SIST EN 61672-3:2014

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IEC:2013 – 9 –

sound pressure level and frequency as a model specified in the Instruction Manual. In the latter case, any adjustments to be applied when that model of calibrator is coupled to the model of microphone supplied on the sound level meter shall use publicly available data from either the manufacturer of the sound level meter or the manufacturer of the sound calibrator.

NOTE It is possible that publicly available data for a model of sound calibrator that is not specified in the Instruction Manual has not been verified according to IEC 61672-2. 9.2 Information for operation Any adaptor required to couple the microphone of the sound level meter to the sound calibrator shall be available. An Instruction Manual for the sound calibrator also shall be available. If an appropriate sound calibrator, any necessary adaptor, or the Instruction Manual are not available, no periodic tests shall be performed.

9.3 Information for testing For periodic testing of a sound level meter, the sound calibrator shall be shown to conform to the periodic-testing requirements for the applicable performance class of IEC 60942. Conformance shall be demonstrated for sound pressure level, frequency, and total distortion using the methods given in the applicable edition of IEC 60942. Evidence that the sound calibrator conforms to the applicable requirements of IEC 60942 may be provided by documentation from a periodic test performed in accordance with the procedures given in IEC 60942. The laboratory may offer to perform a calibration for the soun

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