IEC TR 61305-6-2005 Household high-fidelity audio equipment and systems - Methods of measuring and specifying the performance - Part 6 Listening tests on loudsp.pdf

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1、 TECHNICAL REPORT IEC TR 61305-6First edition 2005-05Household high-fidelity audio equipment and systems Methods of measuring and specifying the performance Part 6: Listening tests on loudspeakers Single stimulus ratings and paired comparisons Reference number IEC/TR 61305-6:2005(E) Publication numb

2、ering As from 1 January 1997 all IEC publications are issued with a designation in the 60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1. Consolidated editions The IEC is now publishing consolidated versions of its publications. For example, edition numbers 1.0, 1.1 and 1.2 refer

3、, respectively, to the base publication, the base publication incorporating amendment 1 and the base publication incorporating amendments 1 and 2. Further information on IEC publications The technical content of IEC publications is kept under constant review by the IEC, thus ensuring that the conten

4、t reflects current technology. Information relating to this publication, including its validity, is available in the IEC Catalogue of publications (see below) in addition to new editions, amendments and corrigenda. Information on the subjects under consideration and work in progress undertaken by th

5、e technical committee which has prepared this publication, as well as the list of publications issued, is also available from the following: IEC Web Site (www.iec.ch) Catalogue of IEC publications The on-line catalogue on the IEC web site (www.iec.ch/searchpub) enables you to search by a variety of

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8、919 02 11 Fax: +41 22 919 03 00 TECHNICAL REPORT IEC TR 61305-6First edition 2005-05Household high-fidelity audio equipment and systems Methods of measuring and specifying the performance Part 6: Listening tests on loudspeakers Single stimulus ratings and paired comparisons PRICE CODE IEC 2005 Copyr

9、ight - all rights reserved No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Electrotechnical Commission, 3, rue de Varemb, PO Box 131,

10、 CH-1211 Geneva 20, Switzerland Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmailiec.ch Web: www.iec.ch R For price, see current catalogue Commission Electrotechnique Internationale International Electrotechnical Commission 2 TR 61305-6 IEC:2005(E) CONTENTS FOREWORD.3 INTRODUCTION

11、.5 1 Scope.6 2 Normative references .6 3 Test preparation .6 3.1 Characteristics of the listening room6 3.2 Loudspeaker position and seat arrangement .7 3.3 Electrical requirements8 3.4 Level setting8 3.5 Listening levels for programmes8 3.6 Programme material8 3.7 Qualification and number of listen

12、ers.8 3.8 Test duration.8 4 Single stimulus ratings .9 4.1 Test procedure9 4.2 Questionnaire9 4.3 Test sequence.10 4.4 Reliability of judgements .10 4.5 Variance analysis 11 4.6 Factor analysis11 4.7 Quality judgement .12 4.8 Representation of the results.12 4.9 Computer programs.13 5 Paired compari

13、sons14 5.1 Test procedure14 5.2 Test criteria.14 5.3 Test sequence.15 5.4 Number of contradictory judgements .15 5.5 Determination of the scale values15 5.6 Variance analysis 15 5.7 Factor analysis15 Annex A (informative) Example calculation for tests using paired comparison16 Bibliography20 TR 6130

14、5-6 IEC:2005(E) 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ HOUSEHOLD HIGH-FIDELITY AUDIO EQUIPMENT AND SYSTEMS METHODS OF MEASURING AND SPECIFYING THE PERFORMANCE Part 6: Listening tests on loudspeakers Single stimulus ratings and paired comparisons FOREWORD 1) The International Electrotechnical

15、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

16、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 Commit

17、tee 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 acc

18、ordance 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 i

19、nterested 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 resp

20、onsible 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 divergen

21、ce between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication. 6)

22、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

23、 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 public

24、ation. 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 suc

25、h patent rights. The main task of IEC technical committees is to prepare International Standards. However, a technical committee may propose the publication of a technical report when it has collected data of a different kind from that which is normally published as an International Standard, for ex

26、ample “state of the art“. IEC 61305-6, which is a technical report, has been prepared by IEC technical committee 100: Audio, video and multimedia systems and equipment The text of this technical report is based on the following documents: Enquiry draft Report on voting 100/855/DTR 100/905/RVC Full i

27、nformation on the voting for the approval of this technical report can be found in the report on voting indicated in the above table. 4 TR 61305-6 IEC:2005(E) The committee has decided that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC

28、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 bilingual version of this publication may be issued at a later date. TR 61305-6 IEC:2005(E) 5 INTRODUCTIO

29、N This technical report gives recommendations for establishing, conducting and evaluating listening tests. The tests described in this report are to be performed in a room, the size and acoustical properties are similar to those of an average living room. Specific recommendations about the room size

30、, acoustical properties, arrangement of loudspeakers and listeners, and environmental conditions are given. This technical report describes experimental procedures, including recommendations on the choice of programme material and the processing and presentation of the final data. It may be useful t

31、o consider some of the recommendations in AES 20. It should be understood that the topics of experimental design, execution and statistical analysis are complex, and that only the most general guidelines can be given. It is recommended that professionals with expertise of experimental design and sta

32、tistics should be consulted. The use of multichannel formats, principally for domestic presentation of surround audio and cinema is becoming more usual. The procedures described in this report are applicable to any number of channels. If the number of loudspeakers to be tested is high, the paired co

33、mparison listening test is lengthy because each loudspeaker has to be compared with the other. A shorter method is the single stimulus rating. With this method, each object is judged once. The rating is almost independent of the loudspeaker range in test. Each object is rated absolutely, whereas a p

34、aired comparison provides a relative ranking of the order of the loudspeakers in test. Another technical report for listening test has been published as IEC 60268-13 and it is expected that the two technical reports should be combined in the maintenance work 6 TR 61305-6 IEC:2005(E) HOUSEHOLD HIGH-F

35、IDELITY AUDIO EQUIPMENT AND SYSTEMS METHODS OF MEASURING AND SPECIFYING THE PERFORMANCE Part 6: Listening tests on loudspeakers Single stimulus ratings and paired comparisons 1 Scope This technical report applies to loudspeakers conforming to IEC 61305-5 and intended for home use. The purpose of thi

36、s report is, in addition to objective testing according to IEC 60268-5, to establish standards for comparison of the sound characteristics of various loudspeakers with each other. Two test procedures are described: single stimulus ratings; paired comparisons. The procedures described in this report

37、are applicable to any number of channels. NOTE The test procedures are specified for stereo systems. They can be applied to multichannel systems accordingly. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only t

38、he edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 61305-5, High fidelity audio equipment and systems; Minimum performance requirements Part 5: Loudspeakers. IEC 60268-5, Sound system equipment Part 5: Loudspeakers.

39、 ISO 3382, Acoustics Measurement of the reverberation time of rooms with reference to other acoustical parameters. 3 Test preparation 3.1 Characteristics of the listening room The volume of the listening room shall be 80 m 3 20 m 3with a room height of 2,75 m 0,25 m. The room should have a rectangul

40、ar floor plan, whereby the ratio of the sides to each other should not exceed 2:1. A square floor plan is not permitted. TR 61305-6 IEC:2005(E) 7 1,0 0,8 0,6 0,4 0,2 100 1 000 10 000 400 T s f Hz IEC 635/05Figure 1 Range limits for the reverberation time The reverberation time of the room shall be w

41、ithin the range limits shown in Figure 1. The reverberation time shall not change by more than +25 % or 20 % within one octave in the range from 400 Hz to 8 kHz. The reverberation time is to be measured with noise in 1/3 - octave intervals with listeners present as laid down in ISO 3382. Conversion

42、of the reverberation time measured without listeners to one with listeners is permitted. Relevant room resonance resulting from furnishings shall be avoided. The distribution of the absorbing material should be as uniform as possible for all frequencies. In particular, parallel walls shall not be al

43、lowed to reflect sound to a significantly higher degree than the other walls. This also applies to the floor and the ceiling of the listening room. The AF-rated mean level of noise in the testing room may not exceed a value of L AFm = 25 dB. 3.2 Loudspeaker position and seat arrangement The loudspea

44、ker shall be hidden behind an acoustically transparent screen to avoid influencing the listener by its design. The loudspeakers shall be located and listened to in the positions in which they are used normally (as recommended of the manufacturer). This means, for example, loudspeakers designed for p

45、lacement in shelves shall be placed in shelves or in an acoustically equivalent position. The distances from the floor and the ceiling shall correspond to usual positioning. Unless otherwise specified, the distance from the walls shall be at least 0,5 m. The loudspeakers shall be tested in the stere

46、o mode. The angle between the imaginary lines joining the loudspeakers and the listener should be not less than 45 for each listener. The loudspeakers shall be positioned so that the stereo base is constant in each case. Only the two sets of stereo loudspeaker (paired comparison) or the set of stere

47、o loudspeakers to be tested (single stimulus rating) may be arranged to prevent feedback from other loudspeakers. When the paired comparison procedure is used, the centre and height of the line between the loudspeakers of each set shall not vary more than is necessary. If several listeners participa

48、te simultaneously in one test, the seats should be arranged so that all listeners can see the loudspeakers directly when the screen is taken away. 8 TR 61305-6 IEC:2005(E) 3.3 Electrical requirements The loudspeakers shall be fed by equipment with characteristics that do not affect the test results.

49、 The system shall consist of a source, level adjustment, and a power amplifier with a low output impedance and sufficient power (that is, clipping may not occur even at the highest signal levels). The tone control is to be set to a flat position both on the equipment as well as on the loudspeakers. Other settings shall be indicated. Deviations in the flat frequency response shall be less than 0,5 dB in the range from 20 Hz to 2