BS EN 60268-4:2014
$198.66
Sound system equipment – Microphones
| Published By | Publication Date | Number of Pages |
| BSI | 2014 | 58 |
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, Annex C and Annex D.
NOTE
The characteristics specified in this standard do not completely describe the subjective response of the microphone. Further work is necessary to find new definitions and measurement procedures for a later replacement by objective characteristics of at least some of the subjective descriptions used to describe microphone performance.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 7 | English CONTENTS |
| 11 | 1 Scope 2 Normative references |
| 12 | 3 Terms and definitions |
| 13 | 4 General conditions 4.1 General 4.2 Measurement conditions 4.2.1 General |
| 14 | 4.2.2 Rated conditions 5 Particular conditions 5.1 Pre-conditioning |
| 15 | 5.2 Sound source 5.3 Measurement of sound pressure 5.4 Voltage measuring system 5.5 Acoustical environment 5.5.1 General 5.5.2 Free-field conditions |
| 17 | 5.5.3 Diffuse field conditions Tables Table 1 – Reverberation time of the empty room |
| 18 | 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 |
| 19 | 5.6.2 Calibration methods 5.7 Overall accuracy 5.8 Graphical presentation of results 6 Type description (acoustical behaviour) 6.1 Principle of the transducer 6.2 Type of microphone |
| 20 | 6.3 Type of directional response characteristics 6.4 Application profile 7 Terminals and controls 7.1 Marking 7.2 Connectors and electrical interface values 8 Reference point and axis 8.1 Reference point |
| 21 | 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 |
| 22 | 10.2 Rated impedance 10.3 Rated minimum permitted load impedance 11 Sensitivity 11.1 General |
| 23 | 11.2 Sensitivities with respect to acoustical environment 11.2.1 Free-field sensitivity 11.2.2 Diffuse-field sensitivity |
| 24 | 11.2.3 Close-talking or near-field sensitivity 11.2.4 Pressure sensitivity |
| 25 | 11.3 Rated sensitivity 12 Response 12.1 Frequency response 12.1.1 Characteristic to be specified |
| 26 | 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 13.1.2 Methods of measurement |
| 27 | 13.1.3 Graphical presentation of results |
| 28 | 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 14.2.2 Method of measurement |
| 29 | 14.3 Harmonic distortion of the nth order (n = 2, 3,…) 14.3.1 Characteristic to be specified 14.3.2 Method of measurement |
| 30 | 14.4 Difference frequency distortion of second order 14.4.1 Characteristic to be specified 14.4.2 Method of measurement 15 Limiting characteristics 15.1 Rated maximum permissible peak sound pressure 15.2 Overload sound pressure 15.2.1 Characteristic to be specified |
| 31 | 15.2.2 Method of measurement 16 Balance 16.1 Balance of the microphone output 16.2 Balance under working conditions Figures Figure 1 – Balance of the output |
| 32 | 17 Equivalent sound pressure level due to inherent noise 17.1 Characteristic to be specified 17.2 Method of measurement Figure 2 – Balance under working conditions |
| 33 | 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 |
| 34 | 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 19.3.2 Method of measurement |
| 35 | Figure 3 – Measurement set-up for wind influence |
| 36 | Figure 4 – Wind generators, type 1 (Figure 4a) and type 2 (Figure 4b) |
| 37 | 19.4 Transient equivalent sound pressure due to “pop” effect 19.4.1 Characteristic to be specified |
| 38 | Figure 5 – Electrical and mechanical set-up for the measuring of the “pop” effect |
| 39 | 19.4.2 Method of measurement 20 Electromagnetic compatibility (EMC) 20.1 Regulatory requirements Table 2 – Reference signal and characteristics |
| 40 | 20.2 Requirements for preserving programme quality Table 3 – Examples of EMC regulations and standards Table 4 – Basic EMC standards and their application to microphones |
| 41 | 20.3 Performance criteria 20.3.1 Criterion A 20.3.2 Criterion B 20.4 Testing for immunity to disturbances in the presence of acoustical noise 20.5 Immunity to frequency-modulated radiated disturbances |
| 42 | 20.6 Immunity to magnetic fields 20.7 Immunity to ripple on d.c. power supply 20.8 Permanent magnetic field 20.9 Evaluation and reporting of the test results |
| 43 | 21 Physical characteristics 21.1 Dimensions 21.2 Weight 21.3 Cables and connectors 22 Classification of the characteristics to be specified |
| 44 | Table 5 – Classification of characteristics |
| 46 | 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 |
| 47 | A.2 Front-to-rear sensitivity index (0° – 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 |
| 48 | 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 |
| 49 | Annex B (informative) Sound insulation device Figure B.1 – Sound insulation device |
| 50 | Annex C (informative) Simplified procedure for “pop” measurements C.1 General C.2 Measurement set-up C.3 Measurement procedure |
| 51 | C.4 Approximate inclusion of different frequency responses |
| 52 | Figure C.1 – Measurement set-up Figure C.2 – Test fixture for the sound field sensitivity |
| 53 | Annex D (informative) Recommendations for professional digital microphones D.1 General D.2 Data sheets for digital microphones Table D.1 – Classification of the characteristics recommended to be specified |
| 55 | Table D.2 – Additional digital characteristics to be specified |
| 56 | Bibliography |
