This part of GB/T20441 specifies the classification, characteristics, mechanical dimensions and electroacoustic characteristics of working standard microphones used in measurement systems for determining sound pressure. GB/T 20441.4-2006 Measurement Microphones Part 4: Specifications for Working Standard Microphones GB/T20441.4-2006 Standard Download Decompression Password: www.bzxz.net
This part of GB/T20441 specifies the classification, characteristics, mechanical dimensions and electroacoustic characteristics of working standard microphones used in measurement systems for determining sound pressure.

ICS17.140.50
National Standard of the People's Republic of China
GB/T 20441.42006/IEC 61094-4: 1995Measurement microphones-
Part 4: Specifications for working standard microphones(IEC 61094-4:1995, IDT)
2006-08-23 Issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Standardization Administration of the People's Republic of China
2007-02-01 Implementation
Normative references
Terms and definitions:
Reference environmental conditions
Classification of working standard microphones
5.1 Overview
Type identification
6 Characteristics of working standard microphones
Sensitivity
Equivalent front cavity volume
Upper limit of dynamic range of microphone
Linear range of microphone sensitivity level
Influence of static pressure on microphone sensitivity
Influence of temperature on microphone sensitivity
Influence of humidity on microphone sensitivity
Stability of microphone sensitivity
Pressure equalization leakage
Mechanical dimensions·
Electroacoustic performance indicators
Identification mark
GB/T 20441.4—2006/1EC 61094-4:19951
Appendix A (informative) Reference structure for temporary grounding shielding of WS3 type microphones
Mechanical structure of microphone
Tolerance curve of frequency response on logarithmic frequency coordinates Figure A.1 Reference structure for temporary grounding shielding of WS3 type microphones Table
Nominal mechanical dimensions and tolerances of the working standard microphone in Figure 1 Table 2 Electroacoustic performance indicators of the working standard microphone Table 3 Tolerance of frequency response
GB/T 20441 "Measurement Microphones" is divided into seven parts: Part 1: Laboratory standard microphone specification: CB/T 20441.4—2006/IEC 61094-4:1995 - Part 2: Primary level method for sound pressure calibration of laboratory standard microphones using the reciprocity technique; - Part 3: Primary level method for free field calibration of laboratory standard microphones using the reciprocity technique; - Part 4: Specifications for working standard microphones, - Part 5: Calibration method for working standard microphones by comparison method; - Part G: Electrostatic exciter for determining frequency response 1 - Part 7: Difference between self-field sensitivity and sound pressure sensitivity of laboratory standard microphones. This part is Part 4 of GB/T 20441. This part is equivalent to IEC61094-4:1995 "Measurement Microphones Part 4: Specifications for Working Standard Microphones 3 (English version). For ease of use, this part has been edited as follows: a) The comma " as a decimal point is replaced by a decimal point \\, except in the foreword of the international standard;
(c) "IEC/D1S1094-3:199×\ is changed to \IEC61094-3:1995", and the footnotes in the original text are deleted; a) "open circuit sensitivity" in 6.1 is changed to "sensitivity calculated according to the open circuit voltage", e) In Chapter 2, the documents cited in the main text for date references are changed to date references; f) "α\" in Table 3 is changed to "一", which is a typographical error in the original text. Appendix A of this part is an informative annex.
This part was proposed by the Ministry of Information Industry of the People's Republic of China. This part is under the jurisdiction of the National Technical Committee for Standardization of Electroacoustics (SAC/TC23): The main drafting units of this part: Hengyang Instrument and Electrical Equipment Co., Ltd., the Third Research Institute of Zhongyuan Electronic Technology Group Corporation, the Institute of Acoustics of the Chinese Academy of Sciences, Shenzhen Metrology and Quality Inspection Institute, China Institute of Metrology, Nanjing University. The main drafters of this part are: Liu Xiangheng, Weng Tailai, Zhang Ruwei: Zhang Guoqing, Zou Xinmin, Zhang Mei'e, Zhao Qichang. Date
1 Scope
Measurement microphones
GB/T 20441.4—2006/1EC 61094-4:1995 Part 4: Specification for working standard microphones
This part of GB/T 20441 applies to working standard microphones. This part specifies the mechanical dimensions and electroacoustic properties of working standard microphones used for determining sound pressure in measurement systems. These microphones are used as transfer standards in the calibration of acoustic measuring instruments. This part specifies the classification method of working standard microphones, and divides microphones into several categories according to their size and performance, so as to standardize measurement systems, calibrate measurement systems and microphones with acoustic calibrators, and the interchangeability of microphones in measurement and calibration systems. This part does not explain the transducer principle of working standard transmitters. 2 Normative references
The clauses in the following documents become clauses of this part through reference in this part of GB/T 20411. For dated references, all subsequent amendments (excluding corrigenda) or revisions are not applicable to this part. However, parties to agreements based on this part are encouraged to explore whether the latest versions of these documents can be used. For undated references, the latest versions apply to this part.
GB/15173—1994 Sound calibrator (eqv1EC 60942:1988)TEC61091-1:1992 Measurement microphones: Part 1: Specification for laboratory standard microphones1EF 61091-2:1992 Measuring microphones Part 2: Primary level method for sound pressure calibration of laboratory standard microphones using the reciprocity technique
IEL61094-3:1995 Measurement microphones Part 3: Primary level method for self-field calibration of laboratory standard microphones using the reciprocity technique
ISb: 1993 Guide to the expression of measurement uncertaintyANSI B1.11982 Unified inch threads
3 Terms and definitions
The terms and definitions established in IEC61094-1 and the following terms and definitions apply to this part of GB/T 20441. 3.1
Working standard microphone A microphone that can be calibrated by at least one of the following methods: a) the method specified in IEC 610S4-2:1992 or IEC61094-3:1995; b) comparison with a calibrated laboratory standard microphone: using the sound calibrator specified in GB/T 1:173-1994. The working standard microphone should meet the requirements for mechanical dimensions and electroacoustic performance, especially the requirements for time stability and correlation with environmental conditions.
The principal axis of microphone is the straight line passing through the center of the microphone diaphragm and perpendicular to the diaphragm. 1) In the absence of corresponding international standards, refer to ANSI B.1. GB/T 20441.4-2006/IEC 61094-4:19953.3
reference plane of microphone The plane perpendicular to the main axis of the microphone and close to the microphone guard grille3. 4
effective frout volame of a microphone The volume of air with the same Lushun as the cavity defined by the reference plane of the microphone, the diaphragm and the outer cylindrical surface on the reference plane under reference conditions. The cavity contains the equivalent volume of the microphone structure. The equivalent front cavity volume is usually a function of frequency.3. 5
correction grille grid
A grid of a specific shape that replaces the conventional protective grid of the microphone to change the indicative response of the microphone and thus change the acoustic type of the microphone
4 Reference environmental conditions
The reference environmental conditions are:
——Temperature: 23.0℃
——Static pressure 101.325kPa
Relative humidity, 30%
Note: This section chooses the test temperature of 23.0℃ because most of the actual standards require that the test be carried out at or close to this temperature. 5 Classification of working standard microphones
5.1 Overview
The sound pressure in a given sound field is usually related to the position. Ideally, it is measured at a certain point with a transducer of infinitesimal size and infinite acoustic impedance. However, the actual size and impedance of the microphone, as well as the installation of the microphone, will cause the measured value of the sound to deviate from the ideal situation:
Taking into account the influence of diffraction, sensitivity can be defined corresponding to various ideal sound fields, such as sound pressure sensitivity, free field sensitivity and diffuse field sensitivity. Microphones are usually designed to make one of the three sensitivities mentioned above basically independent of frequency over the widest possible frequency range.
5.2 Type designation
Working standard microphones are described by a mnemonic symbol consisting of the letters WS (the initials of the English words "working" and "standard"), followed by a number indicating the mechanical structure, and a third letter indicating the electroacoustic characteristics of the microphone. The third letter may be P, F or D, indicating that the pressure, free-field or diffuse-field sensitivity of the microphone is approximately independent of frequency over the widest possible frequency range. For example, a type designation of WS2P indicates a working standard microphone of type 2 mechanical structure with an approximately constant pressure sensitivity as a function of frequency. The type designation does not prevent these microphones from being used under other conditions and, with appropriate corrections, may be used in pressure, free or diffuse field conditions.
6 Characteristics of working standard microphones
6.1 Sensitivity
The sensitivity of a microphone is the sensitivity calculated from the open-circuit voltage as defined in [EC 61094-1:1992]. If the insertion voltage technique is used to determine WSI and WS2 For the sensitivity of the microphone, the grounded shield reference structure given in IEC 61094-1:1992 can be used. For WS3 type, the temporary grounded shield reference structure given in Appendix A can be used. Note: If the microphone has a guard grid, it will affect the free field sensitivity and diffuse field sensitivity. The manufacturer should indicate whether the sensitivity given is with or without a guard grid. By definition, the acoustic sensitivity of the microphone has nothing to do with the presence or absence of a guard grid. However, when the microphone is used to measure the sound pressure in a very small cavity, the microphone guard grid still has an effect. 3
6.2 Equivalent front cavity volume
GB/T 20441.4—2006/1EC 61094-4: 1995 When the microphone is calibrated with a sound calibrator (see 5.2d) in GB/T15173-1994) and the microphone is used in a small coupling cavity such as an ear simulator, the equivalent front cavity volume of the microphone is an important parameter. The equivalent front cavity volume should be given as a function of frequency in the frequency range of 160 Hz to 1000 Fz: Note: The method for measuring the equivalent front cavity volume is given in E.2 of Appendix E of IEC61094-2:1992. 3 The upper limit of the dynamic range of the microphone
The upper limit of the dynamic range is given in sound pressure level, in the range of 160 Hz to 1 000 Fz Hz frequency range caused by the sound pressure level of the total spectrum fluctuation is %
Note: Before the commercialization of 1000Hz or 1000Hz frequency range, there is no method for determining the upper limit of the dynamic range that has been recognized by the philosopher. 6.4 Linear range of microphone sensitivity level
Under reference conditions, at any frequency in the range of 160Hz to 1000Hz, when the sound pressure level changes within the range specified in item 6 of Table 2, the change in the microphone sensitivity level should not exceed 0.2 B. Note: In order to determine the desensitization level at the minimum sound pressure level in the linear range, a narrow-band filter is required. The filter band should be narrow enough to ensure that the relatively large inherent noise of the signal does not affect the final result. 6.5 Effect of static pressure on acoustic sensitivity The sensitivity spot of a microphone is related to static pressure, which affects the impedance of the air in the cavity behind the diaphragm. In the range of 65 kPa to 11 kPa, the effect of static pressure should be given as a function of frequency. Note: At present, it is impractical to determine the effect of static pressure on free-field error and diffusion sensitivity. Comparative techniques can be used in environmental test chambers.
6.6 Effect of temperature on acoustic sensitivity
Small and slow temperature changes usually cause reversible changes in sensitivity. Large or rapid temperature changes (temperature shocks) can cause permanent changes in microphone sensitivity. In the range of -1cc to +57, the effect of temperature on sensitivity should be given as a function of frequency. Note: At present, it is impractical to measure the effect of humidity on free-field sensitivity and diffuse-field sensitivity. Comparison techniques can be used in environmental test chambers.
Effect of humidity on microphone sensitivity
The sensitivity of microphones is related to relative humidity. The effect of relative humidity on sensitivity should be given as a function of frequency in the range of 10% to 90% relative humidity under test temperature and static pressure conditions. NOTE: At present, it is not practical to determine the effect of relative humidity on free-field sensitivity and diffuse-field sensitivity. This can be done by using a comparison technique in an environmental chamber.
Stability of microphone sensitivity
Even when stored under typical atmospheric conditions, the sensitivity of a microphone will vary over a period of time. The stability coefficient should be given for a frequency point in the range of 200 Hz to 1 000 Hz under reference ambient conditions. 6.9 Pressure equalization
The diaphragm back cavity is equipped with a narrow pressure equalizer to ensure equal static pressure on both sides of the diaphragm. At very low pressures, the sound pressure is also fully equalized by the pressure equalizer. Therefore, the free-field sensitivity and diffuse-field sensitivity will be significantly lower than the sound pressure sensitivity. The sound pressure equalization can be described by the minimum time constant or lower limit of the pressure equalizer and back cavity system. The lower limit is defined as the free-field sensitivity level is 3 lower than the acoustic sensitivity level at 250 Hz. dB, and shall indicate whether the voltage-equalizing tube is connected to the outside world through a small hole or enters the preamplifier from the back of the microphone.
7 Specifications
7.1 Mechanical dimensions
The mechanical structure of the working standard microphone shall comply with the requirements of Figure 1, and its nominal dimensions and tolerances shall comply with the provisions of Table 1. The working standard microphone is usually equipped with a protective grille to prevent accidental damage to the diaphragm. For microphones of type WSRP (n=1,2,3), the protective grille shall be removable. For other types of microphones, the protective grille may be fixed or removable. The manufacturer shall specify the maximum pressure that can be applied to the central electrical contact of the microphone without causing a significant change in the actual electroacoustic performance of the microphone.
Protection mutual
Mechanical structure of microphone
Reference plane
Nano-end
Table 1 Nominal mechanical dimensions and differential dimensions of the working standard microphone in Figure 1 Symbol
Thread length
Thread length of the mountain
7.2 Electroacoustic performance indicators
WSIP/F/D type
#23.77±8:9*
+23. 77±0. 1
23, 11
>12, 2
60 UNS-2B
WS2P/F/D type
13. 2 +9:r
p12.7±0. 1
60 UNS-2B
Units are meters
WS3P/F/D type
6. 35 — 0. 05
60UNS-2B
Table 2 gives the electroacoustic performance indicators of the working standard microphone. The manufacturer shall provide all indicators except item 12 by type, and shall give the data of items 1 and 2 separately. For WS1 and WS2 microphones, the sensitivity given should be clearly open-circuit sensitivity. If other sensitivities valid under other conditions are given, the conditions should be stated.
For WS3 microphones, Appendix A gives the preferred ground shield reference structure. If a different structure is used or other structures are used to connect to the preamplifier, the manufacturer should indicate this. G8/T 20441.4—2006/1EC 61094-4;1995 The sensitivity level should be given with a resolution of 0.1 dB or better, and the measurement uncertainty calculated in accordance with ISO guidelines should also be given: The frequency should be given in a curve together with the tolerance curve shown in Figure 2: The tolerance values ​​are given in Table 3. In addition, it is recommended to give typical values ​​of the difference between the free field sensitivity level and the sound pressure sensitivity level, and the difference between the diffuse field sensitivity and the sound pressure sensitivity level in the form of frequency numbers
The manufacturer should specify the basic requirements for the preamplifier or amplifier connected to the microphone that can meet the electroacoustic indicators listed in Table 2, for example, the minimum input impedance of the preamplifier, the polarization voltage and the minimum source impedance of the polarization voltage source should be stated when possible. B
Note: f, f1,The method is specified in Table 2. 0. 25./
2 Indifference curve of frequency response on logarithmic frequency coordinates 7.3
Identification mark
Each working standard microphone shall be engraved with the model specified by the manufacturer and the individual product serial number. 2 Electroacoustic performance indicators of working standard microphones: Sensitivity (base pressure is 1Pa)
Chick response
See Figures 2 and ±3
Equivalent overall volume
Equivalent bulk modulus
(only for P type)
Dynamic range
(base pressure is 20μPa)
In the range of 200Hz to 1 000Hz, the sensitivity level at f is specified on the tolerance curve in Figure 2:
In the range of 200Hz to 1 000Hz, the sensitivity level at f is specified on the tolerance curve in Figure 2:
In the range of 150Hz to 1 000Hz, the sensitivity level at 200Hz to 500Hz is specified on the tolerance curve in Figure 2: Hz
In the range of 160Hz to 1G00Hz
Distortion is 3 years old
WSIP/FD type WS2P.FD type WS3P.FD type -34
108000
10~16 000
:0~31 600
GB/T20441.4—2006/IEC61094-4:1995 Item
Linear range
(Baseline 20μPa)
Pressure coefficient
Temperature coefficient
Relative sensitivity coefficient
Average pressure time constant>
Long-term stability coefficient
Short-term stability coefficient\
Table 2 (continued)
WS1I/F/D voltage
In the range of 1 Hz to 1000 Hz
Sensitivity level changes by 0.2 dB
See 6, 6
In the range of 15℃ to 25℃
In the range of 200Hz to 1000Hz
In the range of 15℃ to 25℃
At 200Hz to 1000Hz
10~130
W52P/F/D type
WS3P/F/D type
25~-135
-0. 03~40. 03
- 0. 03 ~ +0. 03
-0. 001~+0. 001
According to the type identification, the frequency response of the sound pressure, diffuse field and free field sensitivity levels respectively. Unless there is a special purpose, the time constant should not be greater than 15. Otherwise, the short-term stability requirements may not be met. 2)
40~145
dB/kPa
For microphones with pressure equalization leakage that cannot be captured by a first-order system, its order should be stated, and its 3dB lower frequency limit should be stated, without the pressure equalization time constant.
At least five times within 10 days, the interval between each test should not be less than 24h (see IEC6:094-1:1992 3.15) 5) The manufacturer should give the nominal value and its tolerance within the specified frequency range. Table 3
Frequency/Hz
Frequency response differential
WS2 type
+2. 0. 08
Unit: fraction
WS3 type
-2, 0. - 88
Frequency/Hz
10 000
20 000
25 000
40 000
50 000
≥50a0g
WS1 type
+2, 0,-6. 0
-2. 0.-10. 0
+2. 0. -80
Table 3 (continued)
GB/T20441.4-—2006/IEC61094-4:1995Unit: decibel
WS2 type
+2. 0. -6. 0
+2.0,10. 0
WS3 type
+2. 0. --8. 0
+2.0,—10. 0
+2.0,—8
GB/r20441.4—2006/IEC61094-4:1995 Appendix A
(Informative Appendix)
Temporary grounded shield reference structure for WS3 microphone According to the requirements of [EC61094-1:2000, the open-circuit voltage of the microphone is measured through a grounded shield device of a specified form. For WS1 and WS2 microphones, the grounded shield structure specified for laboratory standard microphones in IEC61094-1:2000 may be used. If the insertion voltage technique is used to determine the sensitivity of a WS3 microphone, it is recommended to use the temporary grounded shield reference structure shown in Figure A.1.
Unit is meter
4±0.1
Φ3. 5 ± 0. 1
Microphone installation
Sheet
7. 4±0. 1 1. 5±0. 2
State A, 1 hand WS3 type sensor temporary grounding shielding reference structure 8
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Frequency/Hz
Tolerance of frequency response
WS2 type
+2. 0. 08
Unit: Partial
WS3 type
-2, 0. - 88
Frequency/HzwwW.bzxz.Net
10 000
20 000
25 000
40 000
50 000
≥50a0g
WS1 type
+2, 0,-6. 0
-2. 0.-10. 0
+2. 0. -80
Table 3 (continued)
GB/T20441.4-—2006/IEC61094-4:1995Unit: decibel
WS2 type
+2. 0. -6. 0
+2.0,10. 0
WS3 type
+2. 0. --8. 0
+2.0,—10. 0
+2.0,—8
GB/r20441.4—2006/IEC61094-4:1995 Appendix A
(Informative Appendix)
Temporary grounded shield reference structure for WS3 microphone According to the requirements of [EC61094-1:2000, the open-circuit voltage of the microphone is measured through a grounded shield device of a specified form. For WS1 and WS2 microphones, the grounded shield structure specified for laboratory standard microphones in IEC61094-1:2000 may be used. If the insertion voltage technique is used to determine the sensitivity of a WS3 microphone, it is recommended to use the temporary grounded shield reference structure shown in Figure A.1.
Unit is meter
4±0.1
Φ3. 5 ± 0. 1
Microphone installation
Sheet
7. 4±0. 1 1. 5±0. 2
State A, 1 hand WS3 type sensor temporary grounding shielding reference structure 8
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Frequency/Hz
Tolerance of frequency response
WS2 type
+2. 0. 08
Unit: Partial
WS3 type
-2, 0. - 88
Frequency/Hz
10 000
20 000
25 000
40 000
50 000
≥50a0g
WS1 type
+2, 0,-6. 0
-2. 0.-10. 0
+2. 0. -80
Table 3 (continued)
GB/T20441.4-—2006/IEC61094-4:1995Unit: decibel
WS2 type
+2. 0. -6. 0
+2.0,10. 0
WS3 type
+2. 0. --8. 0
+2.0,—10. 0
+2.0,—8
GB/r20441.4—2006/IEC61094-4:1995 Appendix A
(Informative Appendix)
Temporary grounded shield reference structure for WS3 microphone According to the requirements of [EC61094-1:2000, the open-circuit voltage of the microphone is measured through a grounded shield device of a specified form. For WS1 and WS2 microphones, the grounded shield structure specified for laboratory standard microphones in IEC61094-1:2000 may be used. If the insertion voltage technique is used to determine the sensitivity of a WS3 microphone, it is recommended to use the temporary grounded shield reference structure shown in Figure A.1.
Unit is meter
4±0.1
Φ3. 5 ± 0. 1
Microphone installation
Sheet
7. 4±0. 1 1. 5±0. 2
State A, 1 hand WS3 type sensor temporary grounding shielding reference structure 8
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