BS EN IEC 60268-4:2018
$198.66
Sound system equipment – Microphones
| Published By | Publication Date | Number of Pages |
| BSI | 2018 | 60 |
This part of IEC 60268 specifies methods of measurement for the electrical impedance, sensitivity, directional response pattern, dynamic range and external influences of sound system microphones, and also details the characteristics to be specified by the manufacturer.
It applies to sound system microphones for all applications for speech and music. It does not apply to measurement microphones, but it does apply to each audio channel of microphones having more than one channel, for example for stereo or similar use. It is also applicable to flush-mounted microphones and to the analogue characteristics of microphones with digital audio output.
For the purposes of this International Standard, a microphone includes all such devices as transformers, pre-amplifiers, or other elements that form an integral part of the microphone, up to the output terminals specified by the manufacturer.
The major characteristics of a microphone are considered in Clauses 6 to 21. Additional characteristics are considered in Annex A and Annex C.
NOTE The characteristics specified in this document do not describe the subjective response of the microphone. Further work is necessary to find new definitions and measurement procedures for a later introduction of objective characteristics for at least some of the subjective descriptions used to describe microphone performance.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 5 | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications |
| 7 | CONTENTS |
| 11 | FOREWORD |
| 13 | 1 Scope 2 Normative references |
| 14 | 3 Terms and definitions |
| 15 | 4 General conditions 4.1 General 4.2 Measurement conditions 4.2.1 General |
| 16 | 4.2.2 Rated conditions |
| 17 | 5 Particular conditions 5.1 Pre-conditioning 5.2 Sound source 5.3 Measurement of sound pressure 5.4 Voltage measuring system 5.5 Acoustical environment 5.5.1 General |
| 18 | 5.5.2 Free-field conditions |
| 19 | 5.5.3 Diffuse field conditions |
| 20 | 5.5.4 Microphone coupled to a sound source by means of a small cavity coupler 5.6 Methods of measuring frequency response 5.6.1 Point-by-point and continuous sweep frequency methods Tables Table 1 – Reverberation time of the empty room |
| 21 | 5.6.2 Calibration methods 5.7 Overall accuracy 5.8 Graphical presentation of results |
| 22 | 6 Type description (acoustical behaviour) 6.1 Principle of the transducer 6.2 Type of microphone 6.3 Type of directional response characteristics 6.4 Application 7 Terminals and controls 7.1 Marking 7.2 Connectors and electrical interface values |
| 23 | 8 Reference point and axis 8.1 Reference point 8.2 Reference axis 9 Rated power supply 9.1 Characteristics to be specified 9.2 Method of measurement 10 Electrical impedance 10.1 Internal impedance 10.1.1 Characteristic to be specified 10.1.2 Methods of measurement |
| 24 | 10.2 Rated impedance 10.3 Rated minimum permitted load impedance 11 Sensitivity 11.1 General |
| 25 | 11.2 Sensitivities with respect to acoustical environment 11.2.1 Free-field sensitivity |
| 26 | 11.2.2 Diffuse-field sensitivity 11.2.3 Close-talking and near-field sensitivity |
| 27 | 11.2.4 Pressure sensitivity 11.3 Rated sensitivity 12 Response 12.1 Frequency response 12.1.1 Characteristic to be specified |
| 28 | 12.1.2 Method of measurement 12.1.3 Graphical presentation of results 12.2 Effective frequency range 12.2.1 Characteristic to be specified 12.2.2 Method of measurement 13 Directional characteristics 13.1 Directional pattern 13.1.1 Characteristic to be specified |
| 29 | 13.1.2 Methods of measurement |
| 30 | 13.1.3 Graphical presentation of results 13.2 Directivity index 13.2.1 Characteristic to be specified 13.2.2 Method of measurement 14 Amplitude non-linearity 14.1 General 14.2 Total harmonic distortion 14.2.1 Characteristic to be specified |
| 31 | 14.2.2 Method of measurement 14.3 Harmonic distortion of the nth order (n = 2, 3,…) 14.3.1 Characteristic to be specified 14.3.2 Method of measurement |
| 32 | 14.4 Difference frequency distortion of second order 14.4.1 Characteristic to be specified 14.4.2 Method of measurement |
| 33 | 15 Limiting characteristics 15.1 Rated maximum permissible peak sound pressure 15.2 Overload sound pressure 15.2.1 Characteristic to be specified 15.2.2 Method of measurement 16 Balance 16.1 Balance of the microphone output Figure 1 – Balance of the output |
| 34 | 16.2 Balance under working conditions 17 Equivalent sound pressure level due to inherent noise 17.1 Characteristic to be specified 17.2 Method of measurement Figures Figure 2 – Balance under working conditions |
| 35 | 18 Ambient conditions 18.1 General 18.2 Pressure range 18.3 Temperature range 18.4 Relative humidity range 19 External influences 19.1 General 19.1.1 Specification and methods of measurement |
| 36 | 19.1.2 Other external interferences 19.2 Equivalent sound pressure due to mechanical vibration 19.2.1 Characteristic to be specified 19.2.2 Method of measurement 19.3 Equivalent sound pressure due to wind 19.3.1 Characteristic to be specified |
| 37 | 19.3.2 Method of measurement Figure 3 – Measurement set-up for wind influence |
| 39 | Figure 4 – Wind generators, type 1 (Figure 4a) and type 2 (Figure 4b) |
| 40 | 19.4 Transient equivalent sound pressure due to “pop” effect 19.4.1 General 19.4.2 Characteristic to be specified |
| 41 | 19.4.3 Method of measurement Figure 5 – Electrical and mechanical setupfor the measuring of the “pop” effect |
| 42 | 20 Electromagnetic compatibility (EMC) 20.1 Regulatory requirements 20.2 Requirements for preserving programme quality Table 2 – Examples of EMC regulations and standards |
| 43 | 20.3 Performance criteria 20.3.1 Criterion A 20.3.2 Criterion B Table 3 – Basic EMC standards and their application to microphones |
| 44 | 20.4 Testing for immunity to disturbances in the presence of acoustical noise 20.5 Immunity to frequency-modulated radiated disturbances 20.6 Immunity to magnetic fields 20.7 Immunity to ripple on DC power supply |
| 45 | 20.8 Permanent magnetic field 20.9 Evaluation and reporting of the test results 21 Physical characteristics 21.1 Dimensions 21.2 Weight 21.3 Cables and connectors 22 Classification of the characteristics to be specified |
| 46 | Table 4 – Classification of characteristics |
| 48 | Annexes Annex A (normative) Additional characteristics A.1 Characteristic sensitivity for speech A.1.1 Characteristic to be specified A.1.2 Method of measurement Table A.1 – Speech power weighting factor at octave-band centre frequencies |
| 49 | A.2 Front-to-rear sensitivity index (0° to 180°) A.2.1 Characteristic to be specified A.2.2 Method of measurement A.3 Noise-cancelling index A.3.1 Characteristic to be specified A.3.2 Method of measurement |
| 50 | A.4 Special characteristics for stereo microphones A.4.1 General A.4.2 Included angle of an XY (left-right) microphone A.4.3 Acceptance angle |
| 51 | Annex B (informative) Sound insulation device Figure B.1 – Sound insulation device |
| 52 | Annex C (informative) Recommendations for professional digital microphones C.1 General C.2 Data sheets for digital microphones Table C.1 – Classification of the characteristics recommended to be specified |
| 54 | Table C.2 – Additional digital characteristics to be specified |
| 55 | Annex D (informative) Recommended method for measuring noise levels according to ITU-R BS.468-4 in the digital domain D.1 General D.2 Recommended method Figure D.1 – ITU weighting filter for weighted and unweighted measurements |
| 56 | D.3 Matlab code Figure D.2 – Peak value rectifier scheme Table D.1 – Time constants for the two PVRs |
| 59 | Bibliography |
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