1、BRITISH STANDARD BS6840-1: 1987 IEC268-1: 1985 (including Amendment Nos.1 (March1988) and2 (June1988) to IEC268-1:1986) Sound system equipment Part1: Methods for specifying and measuring general characteristics used for equipment performance IEC title: Sound system equipment. Part1: General (Impleme
2、ntation of CENELEC HD483.1S2) UDC681.84.004.15BS 6840-1:1987 This British Standard, having been prepared under the directionof the Electronic Equipment Standards Committee,was published underthe authority of the BoardofBSI and comes into effect on 30 April 1987 BSI 06-1999 The following BSI referenc
3、es relate to the work on this standard: Committee reference EEL/32 Draft for comment82/21465 DC ISBN 0 580 15839 X Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Electronic Equipment Standards Committee to Technical Committee EEL/32, up
4、on which the following bodies were represented: Association of British Theatre Technicians Association of Sound and Communications Engineers Ltd. Audio Engineering Society British Educational Equipment Association British Kinematograph, Sound and Television Society British Radio and Electronic Equip
5、ment Manufacturers Association British Telecommunications plc. Cable Television Association of Great Britain Consumer Standards Advisory Committee of BSI Consumers Association Council for Educational Technology for the United Kingdom Electronic Components Industry Federation Federation of British Au
6、dio Independent Television Companies Association Industrial Council for Educational and Training Tech Ltd. Institution of Electronic and Radio Engineers Radio Electrical and Television Retailers Association Royal Institute of British Architects Royal National Institute for the Deaf Society of Cable
7、Television Engineers Telecommunication Engineering and Manufacturing Association (TEMA) Training and Educational Systems Testing Bureau Amendments issued since publication Amd. No. Date of issue Comments 6921 May1992 Indicated by a sideline in the marginBS6840-1:1987 BSI 06-1999 i Contents Page Comm
8、ittees responsible Inside front cover National foreword ii 1 Scope 1 2 Units and system of measurement 1 3 Frequencies of measurement 1 4 Quantities to be specified and their accuracy 2 5 Marking and symbols for marking 2 5.1 Marking 2 5.2 Symbols for marking 2 6 Filters, weighting curves and meters
9、 for noise specification and measurement 2 6.1 Wide-band measurement 2 6.2 Weighted measurements 2 7 Simulated programme signal 3 8 Climatic conditions 3 9 Individual specification and type specification 3 10 Graphical presentation of data 3 10.1 General 3 10.2 Scales 3 10.3 Logarithmic scales and p
10、olar diagrams 3 11 Personal safety and prevention of spread of fire 4 12 Measurements in a uniform alternating magnetic field 4 12.1 Method of producing a uniform alternating magnetic field 4 12.2 Measuring the magnetic field strength 4 12.3 Positioning the sample 4 Appendix A Noise weighting networ
11、k and quasi-peak meter 10 Figure 1 Power spectrum of simulated programme signal 7 Figure 2 Filter for simulated programme signal (for pink-noise source) 7 Figure 3 Arrangement of three coils for the production of a uniform alternating magnetic field 8 Figure 4 Search coil for measuring the magnetic
12、field strength 8 Figure 5 Band-pass filter for wide-band noise measurement (amplitude/frequency response limits, see Sub-clause6.1) 9 Figure A.1 Weighting network 10 Figure A.2 Frequency response of the weighting network shown in Figure A.1 11 Figure A.3 Maximum tolerances for the frequency response
13、 oftheweightingnetwork value 12 Table I Frequencies conforming to ISO Standard266 5 Table II Power spectrum of simulated programme signal 6 Table A.I 10 Table A.II 12 Table A.III 12 Publications referred to Inside back coverBS 6840-1:1987 ii BSI 06-1999 National foreword This Part of BS6840 has been
14、 prepared under the direction of the Electronic Equipment Standards Policy Committee and is identical with IEC268-1:1985 “Sound system equipment” Part 1: “General” published by the International Electrotechnical Commission (IEC), as amended by Amendment No.1 dated March1988 and Amendment No.2 dated
15、June1988. This British Standard is also in agreement with Harmonization Document HD483.1S2 published by the European Committee for Electrotechnical Standardization (CENELEC). This Part of BS6840, together with Part2, supersedes BS5428-1:1977 which is withdrawn. BS6840 consists of the following Parts
16、: Part1: Methods for specifying and measuring general characteristics used for equipment performance (supersedes part of BS5428-1); Part2: Glossary of general terms and calculation methods (supersedes part of BS5428-1); Part3: Methods for specifying and measuring the characteristics of sound system
17、amplifiers (supersedes BS5428-2); Part4: Methods for specifying and measuring the characteristics of microphones (previously BS5428-3); Part5: Methods for specifying and measuring the characteristics of loudspeakers (supersedes BS5428-11 and BS5428-11: Supplement1); Part6: Methods for specifying and
18、 measuring the characteristics of auxiliary passive elements (previously BS5428-4); Part 7: Methods for specifying and measuring the characteristics of headphones and headsets (new) 1) ; Part8: Methods for specifying and measuring the characteristics of automatic gain control devices (previously BS5
19、428-7); Part9: Methods for specifying and measuring the characteristics of artificial reverberation, time delay and frequency shift equipment (previously BS5428-8); Part10: Methods for specifying and measuring the characteristics of peak programme level meters (supersedes BS5428-9); Part11: Specific
20、ation for application of connectors for the interconnection of sound system components (supersedes BS5428-5.2); Part12: Specification for applications of connectors for broadcast and similar use (supersedes BS5428-5.3); Part13: Guide for listening test on loudspeakers (new); Part14: Guide for circul
21、ar and elliptical loudspeakers; outer frame diameters and mounting dimensions (previously BS5428-5.1); Part15: Specification for matching values for the interconnection of sound system components (supersedes BS5428-10); Part16: Guide to the “RASTI” method for the objective rating of speech intelligi
22、bility in auditoria (new); Part17: Methods for specifying and measuring the characteristics of standard volume indicators. References to page numbers in the text relate to the IEC page numbers given in brackets at the bottom of each page. 1) In preparation.BS6840-1:1987 BSI 06-1999 iii The Technical
23、 Committee has reviewed the provisions of IEC27, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this British Standard. There is no British Standard corresponding to IEC27. IEC65:1985, to which reference is made in the text, has been harmo
24、nized by CENELEC under HD195 and is implemented by BS415:1990 which is a related standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not
25、of itself confer immunity from legal obligations. Cross-references International standard Corresponding British Standard IEC68 BS2011 Basic environmental testing procedures (Majority of individual Parts are identical) IEC225:1966 BS2475:1964 Specification for octave and one third octave band-pass fi
26、lters (Technically equivalent) IEC263:1982 BS6397:1983 Specification for scales and sizes for plotting frequency characteristics and polar diagrams (Identical) IEC417:1973 BS6217:1981 Guide to graphical symbols for use on electrical equipment (Identical) IEC617 BS3939 Guide to graphical symbols for
27、electrical power, telecommunications and electronics diagrams (Individual Parts are identical) IEC651:1979 BS5969:1981 Specification for sound level meters (Identical) ISO266-1975 BS3593:1963 Recommendation on preferred frequencies for acoustical measurements (Technically equivalent) Summary of page
28、s This document comprises a front cover, an inside front cover, pages i to iv, pages1to14, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv b
29、lankBS6840-1:1987 BSI 06-1999 1 1 Scope This standard applies to sound systems of any kind, and to the parts of which they are composed or which are used as auxiliaries to such systems. This standard deals with the determination of the performance of sound system equipment, the comparison of these t
30、ypes of equipment and the determination of their proper practical application, by listing the characteristics which are useful for their specification and laying down uniform methods of measurements for these characteristics. The standard is confined to a description of the different characteristics
31、 and the relevant methods of measurement; it does not in general specify performance (except in Part10). The complete standard consists of the following parts, in which the characteristics of various parts of sound systems and their methods of measurement are specified; some parts include preferred
32、values: Part1: General; (Uniform characteristics and methods of measurement); Part2: Explanation of General Terms; (Explanation of general terms and calculation methods); Part3: Sound System Amplifiers; (Amplifiers forming part of a sound system for professional and domestic applications); Part4: Mi
33、crophones; (Microphones in professional and domestic applications); Part5: Loudspeakers; (Loudspeakers in professional and domestic applications, treated as entirely passive elements); Part6: Auxiliary Passive Elements; (Attenuators, transformers, filters and equalizers, applied as separate units to
34、 be combined with other separate sound system units); Part7: Headphones and Headsets; (Headphones and headsets intended to be used on the human ear); Part8: Automatic Gain Control Devices; (Limiters and compressors); Part9: Artificial Reverberation, Time Delay and Frequency Shift Equipment; (Devices
35、 commonly employed to achieve special effects in sound systems); Part10: Programme Level Meters; (Peakprogramme meters and vu-indicators); Part11: Connectors for the Interconnection of Sound System Components; (Application of connectors for the interconnection between parts of a sound system); Part1
36、2: Circular Connectors for Broadcast and Similar Use; (Application of connectors for the interconnection between parts of a broadcast or similar professional system); Part13: Listening Test on Loudspeakers; (Listening tests and objective methods for rating the quality of the transmission systems); P
37、art14: Circular and Elliptical Loudspeakers; Outer Frame Diameters and Mounting Dimensions; (Dimensional characteristics of single moving-coil (dynamic) loudspeakers); Part15: Preferred Matching Values for the Interconnection of Sound System Components; (Preferred electrical values for the correct i
38、nterconnection of sound system components). 2 Units and system of measurement The International System of Units (SI units) as given in IEC Publication27: Letter Symbols to be Used in Electrical Technology, is used exclusively in this standard. 3 Frequencies of measurement If measurements are to be m
39、ade at discrete frequencies, then these shall be the frequencies specified as preferred frequencies for acoustical measurements in ISO Standard266, reproduced in Table I. If a measurement relates to a reference frequency, then, in the absence of a clear reason to the contrary, this shall be the stan
40、dard reference frequency of1 000Hz. If a measurement is to be made using only one signal frequency, the signal frequency shall be the chosen reference frequency. If measurements are to be made at a number of different frequencies, the chosen reference frequency shall be included, the other frequenci
41、es being so chosen that the results of the measurements give an adequate representation of the behaviour of the characteristics over the whole of the effective frequency range. If measurements are to be made in frequency bands of constant relative bandwidth, preference shall be given to the one-octa
42、ve and one-third octave bands mentioned in Sub-clause6.2.3.BS 6840-1:1987 2 BSI 06-1999 4 Quantities to be specified and their accuracy Unless otherwise stated, the values of voltage, current, sound pressure, etc.,mentioned in this standard are assumed to be r.m.s. quantities. For most purposes it i
43、s sufficient to measure electrical quantities with an accuracy of 0.15dB and acoustical quantities with an accuracy of 1dB. The accuracy of measurement required depends only on the purpose for which the results are to be used. 5 Marking and symbols for marking 5.1 Marking Terminals and controls shal
44、l be adequately marked to give information regarding their function, characteristics and polarity. The marking shall be such that it must be possible to adjust the controls and to identify their positions with sufficient accuracy in connection with the information given in the user instructions. 5.2
45、 Symbols for marking Marking should preferably be composed of letter symbols, signs, numbers and colours, which are internationally intelligible. Reference is made to IEC Publication27, IEC Publication617: Graphical Symbols for Diagrams, and IECPublication417:Graphical Symbols for Use on Equipment.
46、Index, Survey and Compilation of the Single Sheets. Markings not included in the above-mentioned standards shall be clearly explained in the user instructions. 6 Filters, weighting curves and meters for noise specification and measurement A specification of noise or signal-to-noise ratio shall refer
47、 to noise measured by one of the following methods: 6.1 Wide-band measurement The filter shall be a band-pass filter having a frequency response within the limits shown in Figure 5, page9. (This is identical to the wide-band filter specification in CCIR Recommendation468-3.) A band-pass filter which
48、 has a substantially constant transmission factor between22.4 Hz and22.4kHz, decreasing outside this frequency band at the rates specified for octave-band filters having mid-band frequencies of31.5Hz and16000Hz specified in IEC Publication225: Octave, Half-octave and Third-octave Band Filters intend
49、ed for the Analysis of Sound and Vibrations, has a response falling within the limits of this specification. NOTECare should be taken when there may be strong signals just above or below the band-limits since in this case the results will depend, to some degree, on the individual frequency response of the filter actually used. 6.2 Weighted measurements 6.2.1 Noise (A-weighting) or signal-to-noise (A-weighting) ratio The filter used shall have A-weighting characteristics with toleran
