The provisions of this standard are limited to the measurement of pure tone air conduction audiometry using headphones, and do not include pure tone bone conduction audiometry, masking audiometry and speech audiometry. This standard is applicable to testing people whose hearing may be affected by occupational noise exposure. If it is used for clinical diagnosis or child audiometry, corresponding supplements are required. GB/T 7583-1987 Acoustic Pure Tone Air Conduction Audiometry for Hearing Protection GB/T7583-1987 Standard Download Decompression Password: www.bzxz.net
The provisions of this standard are limited to the measurement of pure tone air conduction audiometry using headphones, and do not include pure tone bone conduction audiometry, masking audiometry and speech audiometry. This standard is applicable to testing people whose hearing may be affected by occupational noise exposure. If it is used for clinical diagnosis or child audiometry, corresponding supplements are required.

1 Introduction
National Standard of the People's Republic of China
Pure tone air conduction audiometry
For hearing conservation purposes
Acoustics--Pure tone air conduction audiometry-For hearing conservation purposes
UDC 5$4.6/.7
GB 7588-87
1.1 This standard specifies the necessary conditions and test procedures for pure tone air conduction audiometry for the purpose of monitoring the hearing of workers in a noisy environment, including the calibration of the audiometer, the maximum permissible ambient noise sound pressure level in the audiometry room and the preparation work. This standard specifies the method of conducting audiometry at fixed frequencies using a manual audiometer with an automatic recording audiometer. Computers or other automated equipment can also be used for audiometric threshold determination. This standard lists the provisions for determining the audiometric level and making audiograms based on the records obtained from the audiometric method adopted. 1.2 The provisions of this standard are limited to pure tone air conduction audiometry using headphones, and do not include pure tone vowel conduction audiometry, masking audiometry and speech audiometry.
1.3 This standard is applicable to testing people whose hearing may be affected by occupational noise exposure. If it is used for clinical diagnosis or children's audiometry, corresponding supplements are required.
1.1 This standard refers to the international standard IS06189-1983 "Acoustics-Pure tone air conduction audiometry for hearing protection". 2 Terms and terms
2.1 Pure tone audiometer
-An electroacoustic instrument with a loop, which can provide a pure tone signal of a specified frequency with a known sound pressure level. 2.2 Manual audiometer
A pure tone audiometer that uses manual control to give signals, select frequencies and hearing levels, and record the subject's responses. 2.3 Automatic recording audiometer
-A pure tone audiometer that controls the hearing level changes by the subject and can automatically record the test results. 2. Computer-controlled audiometer
A pure tone audiometer that produces computer-controlled test steps. Any electronic device that can program and control the test steps is referred to as a computer.
2.5 Air conduction
The process by which sound is transmitted to the inner ear through the outer ear and middle ear in the air. 2.6 Auditory perception
A person's auditory perception refers to the minimum sound pressure level that can correctly cause hearing in more than half of the repeated tests under specified conditions with a specified sound signal.
2.7 Hearing level
At a specified frequency, the pure tone sound pressure level produced by a specified type of headphones in a specified manner in a specified acoustic coupling cavity or a real ear minus the corresponding standard equivalent auditory perception sound pressure level. 2.B Hearing level
A person's hearing level refers to the auditory perception expressed in hearing level measured at a specified frequency using a specified type of headphones and a specified method. Approved by the National Bureau of Standards on March 27, 1987
Implemented on November 1, 1987
2.9 Audiogram of the test subject
GB 1583-87
The relationship between the hearing threshold level and frequency of the test ear measured under specified conditions and methods, expressed in the form of a graph or table. 3 Audiometer
3.1 General requirements
Audiometers should be manufactured in accordance with the requirements of GB4854-84 "Standard Zero Level for Calibration of Pure Audiometers" and IEC645 "Audiometers" f for Type 4 monitoring air conduction pure tone manual and automatic recording audiometers, and should not be calibrated and maintained in accordance with the provisions of 3.3. The manufacture of computer-controlled audiometers should comply with the requirements of relevant monitoring air conduction pure tone manual audiometers and be operated in accordance with the provisions of 6.1 and 6.3. 3.2 Performance of audiometer
3.2.1 Test tone frequency and hearing level
The audiometer should have at least the following test frequencies: 50%, 1000, 20003000, 4000 and 6000Hz, preferably 8000H2. Its hearing level should preferably include the range of -10 to +70dB, at least including ~70dB. 3.2.2 Order of test tone!
When using a manual or computer-controlled audiometer, the test frequencies should be in the order of 1000, 2000, 3000, 4h (M), 6000 (8000) 500, 1000. After testing one ear, test the other ear with the same amplitude. When using an automatic recording audiometer, the test frequencies should be in the order of 500, 1000, 2000, 3000, 4000, 6000 (8000) Hz. After testing one ear, test the other ear in the same order. 3.2.3 Attenuation rate of automatic recording audiometer
The attenuation rate of automatic recording audiometer is preferably 5dB/s. If necessary, an attenuation rate of 2.5dB/s can also be used. 3.3 Maintenance and calibration
When using the audiometer, it must be calibrated regularly in accordance with the requirements of GB4854*-84 and IEC645. Before starting audiometry every day, an audio test must be performed in accordance with 3.3.1. A subjective calibration test should be performed at least once a week in accordance with 3.3.2, and it is better if it can be performed once a day. An objective calibration test should be performed at least every 3 months in accordance with 3.3.3, and a basic calibration should be performed every two years in accordance with 3.3.4.
3.3.1 Test
An experienced tester with normal hearing should listen carefully at least at three attenuation levels for distortion, transient sounds from the attenuator, pure sound switches, and other unexpected sounds from the audiometer at each test frequency. If any sound is heard that is not expected from the audiometer, the audiometer should be removed from service and repaired. 3.3.2 Objective calibration testbZxz.net
Measure a reference audiogram for a subject with stable hearing whose hearing loss level at each test frequency is no more than 2 dB. Compare the test results of the subject in the subjective calibration test with his reference audiogram. If the hearing loss level at any frequency differs by more than 10 dB, the audiometer should be removed from service and an objective calibration test or basic calibration should be performed. 3.3.3 Objective calibration test
Adjust the attenuator of the hearing instrument to the 70 dB hearing level and measure whether the frequencies of all test tones are within the specified range. If it meets the requirements, measure the sound pressure level of each test tone of the two H-type machines at a hearing level of 70dB, and then compare the measured sound pressure level with the value specified in GB 4854-84 according to the model of headphones used. Check the failure point, the transient sound of the attenuator switch, turn each attenuator of the audiometer to the minimum value, and listen for any inappropriate sound from the audiometer at all test frequencies. If the following problems are found, the audiometer should be stopped from use and basic calibration should be carried out: At 70dB hearing level, one or more frequencies are measured to deviate from the value specified in GB4854-84: 3dB at 500-4000Hz, and more than 5dB at 6000-1800Hz; any other inappropriate sound is heard. 3.8.4 Basic calibration
The audiometer should be calibrated once a year or immediately if any problem is found during the periodic inspection in accordance with 3.3.
GB7583-87
The calibration procedure should be carried out in accordance with the requirements for Type 4 audiometers in GB4854-84 and IFC645, including: frequency accuracy,
|harmonic distortion!
|Accuracy of sound pressure level ||tt| ...
After basic calibration and before reuse, the audiometer room conditions should be checked according to 3.3.1 and 3.3.2.
4.1 Ambient noise
4.1.1 Maximum allowable ambient noise level
In order to avoid the test tone being masked by noise, the ambient noise sound pressure level in the audiometer room should not exceed the allowable range listed in this clause. When the subject is not present, the maximum allowable ambient noise sound pressure level measured in the audiometry room at the position equivalent to the subject's head is calculated using the following formula:
Lmax-h+A
Formula i: Imax-→maximum allowable ambient noise sound level: dB (reference value is 20μPa) t-constant value (Table 1, 2 and Table 3), dBA-half-mean attenuation value of the audiometry earphone (measured in accordance with the method specified in GB7584-87 "Measurement Method for Sound Attenuation of Acoustic Ear Amplifiers"), dB
Note: When the type of audiometry machine A,When the minimum hearing threshold level is less than 1 dB, the maximum permissible ambient noise pressure level in the audiometry room should be changed accordingly, that is, the minimum hearing threshold level to be measured is added to the values ​​given in Tables 1, 2 and 3. For example, if the minimum hearing threshold level to be measured is -10 dB, 10 dB should be subtracted from the value [1] in Tables 1, 2 and 3. When the ambient noise exceeds the values ​​listed in Table 1 by 10 dB or more, even if the minimum hearing level required for the test is greater than 10 dB, the hearing test is still not suitable for use as a test for hearing protection.
4.1.2 Psychological test of ambient noise
If vocal level test cannot be performed, the ambient noise can be tested in the following manner. Use at least two subjects whose hearing level at any test frequency does not exceed DdB (or does not exceed the minimum hearing level required for the test) and compare their audiograms measured in an audiometry room that meets 1,1.1 under the same conditions with those measured in an audiometry room that requires psychoacoustic testing. If the hearing threshold level of the latter is 5 dB or more than that of the former, it indicates that the ambient noise in the test case needs to be reduced.
4.2 Requirements for other environmental conditions
During audiometry, the subject should sit comfortably and should not be disturbed by objects or people around him that are not related to the test. When used in controlled audiometry, the examiner should be able to see the subject clearly, but the subject should not see the operation of the examiner. Table 1
【?3 octave condition center frequency
GB 7583—87
When the minimum hearing threshold level to be measured is dB, the k value and L max representative values ​​of the 1/3 octave band
(reference condition is 20μPa)
Table 2 When the minimum hearing threshold level to be measured is dB, the k value and L max representative values ​​of the octave band
Octave band center frequency
(value 20)
Center frequency of the octave band
CB 758387
丧3When the minimum listening level to be measured is dB, if the ambient noise in the audiometric room exceeds the octave band value and L representative value listed in the table, the listening level measurement should not be performed before further reducing the noise tame
(reference value 20μPa)
Note: The values ​​in Table 1 are based on the negligible audiometric error caused by the masking of the ambient noise at 0 quality. It is recommended to use a low ar value.
When the minimum listening level to be measured is (B), if the octave band analysis of the ambient sound is performed and the octave band sound pressure levels do not exceed the values ​​listed in Table 2, then the audiometry room is suitable for listening level determination. When the minimum listening level to be measured is 0d, if one or more octave band sound levels exceed the values ​​listed in Table 3 without further reduction, then the audiometry room is not suitable for listening level determination. If one or more octave band sound levels are not within the values ​​listed in Table 2 and Table 3, then the room is not suitable for listening level determination. If the sound pressure level is between the values ​​listed in Table 1, the sound pressure level of the 1/3 octave band should be measured to determine whether it exceeds the values ​​listed in Table 1.
② Table 1 is based on the audiometric data of Beyer DT48 headphones and TDH-headphones plus M×41/AR ear pads. 5 Preparation and training of subjects before hearing test The preparation and training of subjects and hearing test should be carried out by experienced professional examiners. Professionals must be trained and passed the assessment.
5.1 Preparation of the Subjects
Recent tinea versicolor may cause a temporary increase in hearing loss. Therefore, according to work needs, the subjects can be taken away from the noisy environment for a certain period of time before the audiometry, or wear high-attenuation ear protectors in advance. Before the audiometry, an otolaryngologist should perform a microscopic examination. If the external auditory canal is found to be blocked, it should be removed. If necessary, the audiometry time can be postponed according to the specific situation. If inflammation or soreness of the external ear is found, the audiometry time should also be postponed for the sake of hygiene. Note: Before the microscopic examination, the audiometry can be performed first. If the result is worse than expected, further examination and Retest. Before the test, pay attention to the following: a. Remove glasses, headwear and hearing aids; b. Push the hair between the earphone and the head away; c. The earphone should be put on by the tester to ensure proper sealing and comfort, and warn the subject not to touch the earphone with his hands; d. Warn the subject to avoid unnecessary activities to avoid extra noise. After everything is ready, let the subject rest for at least half a minute before testing. 5.2 Training of the subject GB 7583—8T
The test method should be clearly explained to the subjects. The instructions include: a. How to indicate when the test tone is just heard, such as extending a finger, raising an arm, or removing the key of the signal indicator. b. How to indicate when the test tone cannot be heard, such as putting down a finger or arm or releasing the key! c. How to indicate that the sound signal is very weak and must be listened attentively and respond as quickly as possible. c. The order of the tones of the sound signal and which tone is tested first. d. In the event of any problem, the subject may ask to suspend the test. After the above instructions, the subjects should be asked whether they have understood. If there are any questions, the instructions should be repeated. 6 Audiometric operation and determination of listening level
6.1 Audiometry with a hand-controlled audiometer
This standard specifies two audiometric methods: the ascending method and the ascending method. The two methods differ only in the way the test tone is given. Note: According to the verification tests of many laboratories, it is shown that there is no significant difference in the hearing threshold level measured by the two methods. However, in terms of test time, the ascending method takes longer than the ascending method. This standard recommends the use of the above method. 6.1.1 Test tone
The test tone should last for 1→2 seconds. After the response is induced, the interval before the test tone is given again should be irregular. However, each interval should not be shorter than the duration of the test tone. 6.1.2 Familiarization
Usually a 100Hz test tone is used, and the attenuator is adjusted to the dB hearing level to input the test tone to the subject. This test tone can cause the subject to respond. If there is no response, the sound level of the test tone is increased by 10dR steps until the subject responds. Then the following familiarization items are performed.
The above test tone is completely attenuated, and then the sound level of the test tone is gradually increased until a response occurs. Test again at the same hearing level for intervals 1 to 2. If the response is consistent, the hearing threshold level can be measured. If it is inconsistent, repeat the above familiarization process. If it fails again for the first time, the explanation and guidance should be repeated. 6.1.3 Accurate measurement
The measurement using the ascending method or the descending method is not interrupted only in the second step of the test. The following is an explanation: Step 1: After the subject is familiar with the 1100H2 test tone by the above method, the first test tone is given in the order specified in 3.1.2 during the formal test at a sound level 10dB lower than the hearing level when the subject reacts. If the subject cannot react, the sound level of the test tone is increased in 5dB steps until the subject reacts.
Step 2:
Ascending method: After the subject reacts, the sound level of the test tone is reduced by 10dB, and then increased in 5dB steps. This is repeated until 3 reactions occur at a certain hearing level in 5 times of the tone. Note:) Sometimes it can be simplified to produce a reaction at the hearing level in 1 to 5 times of each frequency. This is the simplified ascending method. ②Use the ascending method. If the response to the same level of sound is less than 3 times in 5 times (or use the simplified ascending method, if there are less than 2 responses in 3 times), then increase the hearing level of the last response by 10 days, and then repeat the above test steps. The ascending and descending method: After the subject responds: increase the sound level of the test sound by 5dB, and then reduce it by 5dB until there is no response. At this time, reduce the sound level of the test sound by 5dB again, and then increase it by 5dB, and repeat 3 ascending and 3 descending.
Note: The ascending and descending method can sometimes be simplified. That is, in:If the test volume is not lowered by 5dB or the difference between the four minimum response sound levels is not greater than 5dR, two rises and two drops can be used.
The third step is to test the next frequency, which can be started at a sound level 10dB lower than the sound level that can produce a response at the frequency just tested, and if necessary, it can be lower. In this way, the hearing thresholds of all frequencies of the ear are measured. Fourth: Use the same method to measure the other ear.
If the result of the last repeated test of the 1000Hz hearing threshold of the ear tested first is equal to or less than 5dB with the value of the first test, the test of the other ear can be started. If the difference between the two results is equal to or greater than 10dB, all frequencies should be tested repeatedly in sequence until GB 7583--87
meets the above requirements. However, the entire test time should not be too long, and it can be limited to less than 2 minutes, otherwise it may be difficult to obtain reliable results due to fatigue of the subjects.
6.2 Determination of the hearing level by manual audiometry
Depending on the test method used, the hearing threshold level for each ear and each frequency should be determined according to the following procedure. If repeated tests are performed, the results of the repeated tests should be used.
6.2.1 Determination of the hearing level when the ascending method is used In a series of ascending steps, find the lowest sound level that produces at least 3 responses to the sound given 5 times at the same level. This minimum sound level is the hearing level.
Note: If the difference in the minimum response level at a certain frequency is greater than 10 dB when repeated tests are performed, the test should be considered unreliable and the test should be repeated. 6.2.2 Determination of the hearing level when the ascending and descending method is used
For each frequency in each ear, first average the minimum sound level that produces a response to the test tone at each ascending step and the minimum sound level that produces a response at each descending step. Then find the average of the two averages. This average value can be rounded to the nearest whole decibel, which is the hearing threshold level of the frequency.
Note: ① If the difference between the minimum sound levels that cause a response in the ascending or descending series is large (1 dB), the test should be repeated if possible. ② If computer control is used, 6.1 and 6.2 are also applicable and equivalent results are obtained. 6.8 Audiometry with an automatic recording audiometer
6.3.1 Familiarization
When starting to test the first frequency, only start the attenuation system without starting the recording device. Practice for 20 to 30 seconds to observe whether the subject has understood the various operations. After they have understood them, start the recording device. If there are any questions, explain and practice again. 6.3.2 Measurement
After starting the recording device, test each frequency point in sequence until both ears are tested. Without turning on the headphones, allow the subject to rest for 1 minute and then test again, first testing the first two frequencies of the first ear. If the results of the first test are consistent, the test can be ended. If there is an unexpected change of 5 dB, continue to re-test the other frequencies. . 6.4 When determining the hearing level by automatic recording audiometry, if no repeated test is performed at other frequencies, the first test result shall be used. If retesting is necessary, the retest result shall be used. The procedure for determining the hearing threshold level is as follows:
The peaks and valleys in the trace after each frequency conversion and any peaks and valleys equal to or less than 3dB shall not be calculated, and the number of peaks and valleys in each and every frequency hearing trace shall be carefully distinguished: b.
Round the average of the above two averages to the nearest whole decibel. This value is the hearing threshold level of the ear at this time. The hearing threshold level of the frequency. Note: () If the recording of any frequency in the two ears is considered unreliable or any of the following situations occur, the test should be repeated, and at least 10 peaks and valleys should be recorded after removing the valleys with a sum equal to or less than 3dB. The interval between each peak or the interval between the peaks should be within 10dB. 2 If the amplitude of the upper and lower fluctuations of the trace is not large, the simpler "visual average" method can be used, and the result is similar to the result obtained by the method. 6.5 Limitation of airway hearing valve test
If the test result of the hearing level at any frequency in the two ears reaches 40dB When the hearing level is 0.1 or higher, the analysis of the test results should be cautious due to the possibility of cross-hearing. Audiogram
7.1 Drawing of audiogram
The audiogram can be presented in the form of a graph or a chart. The audiogram should clearly indicate the type and model of the audiometer and its standard zero level. When presented in a graph, the horizontal axis usually represents the frequency and the vertical axis represents the hearing level. The width of an octave on the frequency axis should be equivalent to a distance of 20dB on the hearing level axis. It is recommended to use the following symbols to mark the hearing threshold level: Normal: 0
GB T56A7
If there is still no response at the maximum output level of the audiometer, fill in the following symbol at the maximum output level of each frequency: ear
On the audiogram, the center point of the symbol should be drawn at the intersection of the frequency horizontal axis and the hearing level vertical axis of the corresponding frequency and hearing level. If the hearing levels of the two ears at any frequency are equal, but they are to be marked on the same graph, the symbol of the left ear can be drawn inside the symbol of the right ear. Except for the symbol indicating no response, the symbols of other adjacent frequencies can be connected by straight lines. 7.2 Comparison of audiograms
When comparing the hearing levels measured by an automatic recording audiometer with those measured by a hand-drilled audiometer, 3dB should be added to the hearing threshold levels measured by the automatic recording audiometer before comparison. In order to conduct statistical analysis on the hearing threshold level measurement results, the confidence data listed in Appendix A can be used for reference. GB T58887
Appendix A
Confidence of audiometry
(reference)
The following table shows the standard deviation of the hearing level and the representative value of the frequency relationship when the test is repeated according to this standard. Standard deviation of repeated test of hearing level
Additional notes:
201 lines
This standard was reviewed and approved by the National Technical Committee for Acoustic Standardization. The National Technical Committee for Acoustic Standardization
Chairman: Daxian, Vice Chairman: Wu Dasheng, Xu Weiyi, Yu Bo. This standard was proposed by the Basic Acoustics Subcommittee of the National Technical Committee for Acoustic Standardization. The Basic Acoustics Subcommittee
Chairman: Xiang Daxian, Vice Chairman: Wu Wenqiu. The main drafter of this standard is Wang Naiyi.
Standard deviation5 Limitations of air conduction hearing valve test
If the test result of hearing level in any frequency in both ears reaches 40dB hearing level or more, the analysis of the test result should be cautious due to the possibility of cross hearing phenomenon. Audiogram
7.1 Drawing of audiogram
The audiogram can be presented in the form of a graph or a chart. The audiogram should clearly indicate the type and model of the impedance meter and its standard zero level. When presented in a graph, the horizontal axis usually represents the frequency and the vertical axis represents the hearing level. The width of one octave on the frequency axis should be equivalent to the distance of 20dB on the hearing level axis. It is recommended to use the following symbols to mark the hearing threshold level: For ear: 0
GB T56A7
If there is still no response at the maximum output level of the audiometer, fill in the following symbol at the maximum output level of each frequency: For ear: 0
GB T56A7
If there is still no response at the maximum output level of the audiometer, fill in the following symbol at the maximum output level of each frequency: For ear: 0
On the audiogram, the center point of the symbol should be drawn at the intersection of the frequency abscissa and the hearing level ordinate of the corresponding frequency and hearing level. If the hearing levels of the two ears at any frequency are equal, and they are to be marked on the same graph, the symbol of the left ear can be drawn inside the symbol of the right ear. Except for the symbol indicating no response, the symbols of other adjacent frequencies can be connected by straight lines. 7.2 Comparison of audiograms
When comparing the hearing levels measured by an automatic recording audiometer with those measured by a hand-drilled audiometer, 3dB should be added to the hearing threshold levels measured by the automatic recording audiometer before comparison. In order to conduct statistical analysis on the hearing threshold level measurement results, the confidence data listed in Appendix A can be used for reference. GB T58887
Appendix A
Confidence of audiometry
(reference)
The following table shows the standard deviation of the hearing level obtained when the test is repeated according to this standard and the representative value of the frequency relationship Standard deviation of hearing level repeated test
Additional instructions:
201 lines
This standard was reviewed and approved by the National Technical Committee for Acoustics Standardization. The National Technical Committee for Acoustics Standardization
Chairman: Daxian, Vice Chairman: Wu Dasheng, Xu Weiyi, Yu Bo. This standard was proposed by the Basic Acoustics Subcommittee of the National Technical Committee for Acoustics Standardization. The Basic Acoustics Subcommittee
Chairman: Xiang Daxian, Vice Chairman: Wu Wenqiu. The main drafter of this standard is Wang Naiyi.
Standard deviation5 Limitations of air conduction hearing valve test
If the test result of hearing level in any frequency in both ears reaches 40dB hearing level or more, the analysis of the test result should be cautious due to the possibility of cross hearing phenomenon. Audiogram
7.1 Drawing of audiogram
The audiogram can be presented in the form of a graph or a chart. The audiogram should clearly indicate the type and model of the impedance meter and its standard zero level. When presented in a graph, the horizontal axis usually represents the frequency and the vertical axis represents the hearing level. The width of one octave on the frequency axis should be equivalent to the distance of 20dB on the hearing level axis. It is recommended to use the following symbols to mark the hearing threshold level: For ear: 0
GB T56A7
If there is still no response at the maximum output level of the audiometer, fill in the following symbol at the maximum output level of each frequency: For ear: 0
GB T56A7
If there is still no response at the maximum output level of the audiometer, fill in the following symbol at the maximum output level of each frequency: For ear: 0
On the audiogram, the center point of the symbol should be drawn at the intersection of the frequency abscissa and the hearing level ordinate of the corresponding frequency and hearing level. If the hearing levels of the two ears at any frequency are equal, and they are to be marked on the same graph, the symbol of the left ear can be drawn inside the symbol of the right ear. Except for the symbol indicating no response, the symbols of other adjacent frequencies can be connected by straight lines. 7.2 Comparison of audiograms
When comparing the hearing levels measured by an automatic recording audiometer with those measured by a hand-drilled audiometer, 3dB should be added to the hearing threshold levels measured by the automatic recording audiometer before comparison. In order to conduct statistical analysis on the hearing threshold level measurement results, the confidence data listed in Appendix A can be used for reference. GB T58887
Appendix A
Confidence of audiometry
(reference)
The following table shows the standard deviation of the hearing level obtained when the test is repeated according to this standard and the representative value of the frequency relationship Standard deviation of hearing level repeated test
Additional instructions:
201 lines
This standard was reviewed and approved by the National Technical Committee for Acoustics Standardization. The National Technical Committee for Acoustics Standardization
Chairman: Daxian, Vice Chairman: Wu Dasheng, Xu Weiyi, Yu Bo. This standard was proposed by the Basic Acoustics Subcommittee of the National Technical Committee for Acoustics Standardization. The Basic Acoustics Subcommittee
Chairman: Xiang Daxian, Vice Chairman: Wu Wenqiu. The main drafter of this standard is Wang Naiyi.
Standard deviation
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