Acoustics?Reference zero for the calibration of audiometric equipment?Part 1:Reference equivalent threshold sound pressure levels for pure tones and supra-aural earphones
Introduction to standards:
This part of GB/T 4854 specifies the reference zero level for pure tone air conduction audiometers. The data described in this part, namely the responses of two different types of standard earphones measured in a coupling cavity in accordance with GB/T 7342, and the responses of other types of supra-aural earphones (specified in 4.3) measured on artificial ears in accordance with GB/T 7614, can be directly used for audiometer calibration. This standard is based on estimates made from data from a number of laboratories responsible for audiometric standardization and scientific publications. The derivation and application of the reference levels recommended in this part are shown in Appendix A. GB/T 4854.1-2004 Reference zero level for acoustic calibration of audiometric equipment Part 1: Reference equivalent threshold sound pressure level of pure tone for supra-aural earphones GB/T4854.1-2004 Standard download decompression password: www.bzxz.net
This part of GB/T 4854 specifies the reference zero level for pure tone air conduction audiometers. The data presented in this part, i.e. the responses of two different types of standard earphones measured in a coupling cavity conforming to GB/T 7342, and the responses of other types of supra-aural earphones (specified in 4.3) measured on artificial ears conforming to GB/T 7614, can be used directly for audiometer calibration. This standard is based on estimates made from data from a number of laboratories responsible for audiometric standardization and scientific publications. The derivation and application of the reference level recommended in this part are given in Appendix A.
GB/T4854 "Acoustic Calibration of Audiometric Equipment Reference Zero Level" includes 8 parts:
Part 1: Reference equivalent A sound pressure level of pure tone for on-ear headphones, GB/T4854.1;
Part 2: Reference equivalent A sound pressure level of pure tone for plug-in headphones, GB/T16402;
Part 3: Reference equivalent sound pressure level of pure tone for bone vibrator, GB/T4854.3;
Part 4: Reference equivalent sound pressure level of narrow-band masking noise Standard level; GB/T4854.4;
Part 5: Standard equivalent closed sound pressure level of pure tone in the frequency range of 8kHz-16kHz (to be formulated);
Part 6: Standard equivalent closed sound pressure level of short-duration test signal (to be formulated);
Part 7: Standard hearing threshold for free field and diffuse field audiometry, GB/T4854.7;
Part 8: Standard equivalent closed sound pressure level of pure tone for earmuff type headphones (to be formulated).
Note: When the second part of this standard was formulated, it had not yet formed a series of standards in China, and its standard number was GB/T16402. When revising this part, it is recommended to change its standard number to GB/T4854.20
This part is the first part of GB/T4854.
This part is equivalent to ISO389-1:1998 "Reference zero level for acoustic calibration audiometric equipment Part 1: Reference equivalent sound pressure level of pure tone for on-ear headphones".
This part replaces GB/T4854.1-1999 "Reference zero level for acoustic calibration audiometric equipment Part 1: Reference equivalent closed sound pressure level for on-ear headphones". Because GB/T4854.1-1999 is equivalent to ISO389-1:1991, ISO revised ISO389-1 in 1998, modified the introduction, references and appendices of the 1991 edition, and replaced ISO389:1991 with ISO389-1:1998.
This part makes editorial changes to the international standards that are equivalent to the international standards.
Appendix A of this part is an informative appendix.
This part was proposed by the Chinese Academy of Sciences.
This part is under the jurisdiction of the National Technical Committee on Acoustics Standardization (CSBTS/TC17).
The drafting units of this part are: Institute of Otolaryngology, General Hospital of PLA, Institute of Acoustics, Chinese Academy of Sciences.
The main drafters of this part are: Gu Rui, Zhang Ruwei, Chen Hongwen, Wu Wenming, Zhang Jucai.
The
previous versions of the standards replaced by this part are:
-GB/T4854-1984, GB/T4854.1-1999.
The provisions of the following documents constitute the provisions of this part through reference in this part of GB3/T4854. For any dated reference, all subsequent amendments (excluding errata) or revisions are not applicable to this part. However, parties to agreements based on this part are encouraged to study whether the latest versions of these documents can be used. For undated references, the latest version shall apply to this part.
GB/T7342 Reference coupling cavity for IEC Irfi calibration of audiometric headphones (GB/T7342-1987, egvIEC60303:1970)
GB/T7614 Wideband artificial ear for calibration of audiometric headphones (GB/T7614-1987, egvIEC60318:1970)
Some standard content:
ICS13.140
National Standard of the People's Republic of China
GB/T 4854.12004/IS0 389-1: 1998 replaces GB/T 4854, 1—1999
Acoustics-Reference zero for the calibration of audiometric equipment--Part 1: Reference eguivalent threshold sound pressure levels for pure tones and supra- aural earphones(IS0 389-1:1998,IDr)
Promulgated on 2004-05-13
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Administration of Standardization of the People's Republic of China
Implementation on 2004-12-01
GB/T 4854.1-2004/ISO 389-1: 1998 GB/T4854 Reference zero level for acoustic calibration of audiometric equipment includes 8 parts: Part 1: Reference equivalent threshold sound pressure level of pure tone for on-ear headphones, GB/T4854.1; Part 2: Reference equivalent threshold sound pressure level of pure tone for invasive headphones, GB/T16402# Part 3: Reference equivalent sound pressure level of pure tone for bone vibrator, GB/T4854.3: Part 4: Reference level of narrow-band masking noise: GB/T4854.4: Part 5: Reference equivalent sound pressure level of pure tone in the frequency range of 8kHz~16kHz (to be formulated): Part 6: Reference equivalent threshold sound pressure level of short-duration test signals (to be formulated) Part 7: Reference hearing threshold for free-field and diffuse-field audiometry, GB/T4854.7! Part 8: Reference equivalent sound pressure level of pure tone for over-ear headphones (to be formulated). Note: When the second part of this standard was formulated, it had not yet formed a series of standards in my country. Its standard number was GB/T16402. When revising this part, it is recommended to change its standard number to GB/T 4851.2. This part is the first part of GB/T4854.
This part is equivalent to ISO389-1:1998 "Acoustic calibration audiometric equipment reference zero level Part 1: On-ear headphones pure tone reference equivalent sound pressure level".
This part replaces GB3/T4854.-1999 Acoustic calibration audiometric equipment reference zero level Part 1: On-ear headphones reference equivalent sound pressure level". Because GB/T4854.1-1999 is equivalent to ISO389-1:1991, ISO revised ISO389-1 in 1998, modified the introduction, references and appendices of the 1991 edition, and replaced ISO389-1:1998 with ISO389-1. 389:1991.
This part makes editorial amendments to the international standards adopted equivalently. Appendix A of this part is an informative document.
This part was proposed by the Chinese Academy of Sciences.
This part is under the jurisdiction of the National Technical Committee for Standardization of Audiometers (CSBTS/TC17). The drafting units of this part are: Institute of Otolaryngology, General Hospital of the People's Liberation Army, Institute of Acoustics, Chinese Academy of Sciences. The main drafters of this part are: Gu Rui, Zhang Ruwei, Chen Hongwen, Wu Wenming, Zhang Jucai. The previous versions of the standards replaced by this part are: GB/T4854-1984, GB/T4854.1-1999. GB/T 4854.1-2004/IS0 389-1: 1998 Introduction
Each part of GB/T 4854 specifies a specific reference zero level for calibrating audiometric equipment. GB/T GB/T4854.1 is applicable to compression earphones and pure-tone air-conduction audiometric equipment; GB/T16402 is applicable to insert earphones and pure-tone air-conduction audiometric equipment; GB/T4854.3 is applicable to pure-tone bone-conduction audiometric equipment; GB/T4854.4 specifies the reference level of narrow-band masking noise; GB/T4854.7 specifies the reference level of listening in the self-field and diffuse field.
GB/T1851-1984, first edition, specifies the standard reference zero level applicable to pure-tone air-conduction audiometers based on the response of certain types of earphones in designated artificial ears or coupling cavities. The five earphone-coupler combinations used are consistent with those used by the standardization laboratories of France, Germany, Britain, the United States and the former Soviet Union at the time. The second set of values of GB/T4854-1984 is the reference level of the United States National Bureau of Standards for the reference The reference equivalent threshold sound pressure level (RETSPL) of 11 pairs of test earphones in a single USA9A type coupler (which complies with the provisions of the US National Standard, later adopted by IEC:303.1990, and now IEC60318-3) is obtained. Most of the earphone-coupler combinations mentioned in the first edition of GB/T4854:1984 are no longer in use. The ISO member countries that originally participated in those works agreed to delete the obsolete data and delete these contents in ISO389:1985. ISO389:1985 only retains the RETSPL of the Telephonics TDH39 type earphone with MX41/AR type pad and the Bcyer DT48 type earphone with EC303:1970 acoustic coupler, which are widely used for audiometry. The difference between the two retained data is mainly due to the difference between the acoustic properties of the coupler and the acoustic characteristics of the general human ear. For the same reason, the data in this part cannot be used to infer other types of earphones not listed in GB/T4854. Until now, the corresponding values have to be obtained by comparing subjective hearing with the specified earphones. In principle, if the RETSPL value is based on a simulated ear whose acoustic characteristics accurately simulate the performance of the average human ear, the RETSPL value obtained is independent of the earphone model. For the devices designed for this day, factory specifications were made in IEC318:1970 (now IEC60318-1) in 1970. Therefore, Annex 1 of IEC389:1985 was developed based on the technical data of RETSPL values obtained by various types of earphones with IEC simulated ears proposed by the laboratories listed in Appendix A. Analysis of these data has resulted in a set of RFTSPI with acceptable tolerances, providing reference audiometric zero levels for a wide range of arbitrary types of inductive earphones. The derivation and data source of these reference values are given in Annex A for reference. Annex 1 specifies the use of reference zero levels instead of the provisions for subjective calibration of supra-aural earphones suitable for different requirements. This promotes the unification and consistency of the expression of listening and reading levels, and is conducive to the improvement and development of the models of on-ear headphones. The data in Annex 1 are incorporated into GB/T4854.1-1999 and are part of it. In Annex 1 of IS389 and ISO389, the RETSPL of the octave frequencies from 125Hz to 8000Hz and the audiometric frequencies 1500Hz, 2, 3000Hz and 6000Hz between them are specified. Because 750Hz is sometimes used as the intermediate pure tone audiometric frequency, Annex 2 of SO389:1985 specifies the RETSPL value of this frequency. In addition, in order to coordinate the intermediate audiometric frequencies used in pure tone audiometry with the commonly used frequencies in acoustic measurements specified in ISO226, Annex 2 specifies the RETSPL values of all pure tones with a frequency span of 1/3 octave in the frequency range of 125Hz to 8000Hz. For further understanding, the detailed process of deriving RETSPL is given in Appendix A. GB/T4854.1:1999 also contains the data of Annex 2 of T. The 750Hz RETSP specified in this part is for calibrating the pure tone of 750Hz fixed frequency set in the audiometer. The RETSPL of other frequencies was originally used for calibrating the pure tone audiometer with continuously variable frequency. But it can also be used for other aspects, such as determining the reference level of masking noise. The frequencies given in ISO389:1985 and Annex 2 are consistent with the frequencies used in GB/T4854.3 for calibrating the reference zero level of bone conduction audiometer. This part specifies 3 groups of RETSPL values. Two of them are about the headphone models described in ISO389:1985. The third group of RFTSPI values is for other types of supra-aural headphones mentioned in ISO389:1985, but they should meet the requirements specified in Annex 1 of ISO389.
1 Scope
GB/T 4854.1—2004/ISO 389-1:1998 Acoustic calibration of hearing test equipment reference zero level
Part 1: Pure tone reference for supra-aural earphones
Equivalent threshold sound pressure level
This part of GH/T 4854 specifies the reference zero level for pure tone air conduction audiometer threshold level scale. The data presented in this part, namely the responses of two different types of standard earphones measured in a coupling cavity in accordance with GB/T 7342, and the responses of other types of supra-aural earphones (specified in 4.3) measured on artificial ears in accordance with GB/T 7614, can be used directly for audiometer calibration.
This standard is based on estimates based on data from a number of laboratories responsible for audiometric standardization and scientific publications. The derivation and application of the reference levels recommended in this part are given in Appendix A. 2 Normative references
The clauses in the following documents constitute the clauses of this part through reference in this part of GB/T 4854. For dated references, all subsequent amendments (excluding errata or revisions) are not applicable to this part. However, parties to agreements based on this part are encouraged to investigate whether the latest versions of these documents can be used. For undated references, the latest versions apply to this part. GB/17342 IEC temporary reference coupler for calibration of audiometric headphones (GB/T 7342-1987, eVIEC: 60303: 19701) GB/T 7614 Wideband artificial ear for calibration of audiometric instruments (GB/T 7614-1987eV FC 60318: 1970) 3 Terms and definitions
The following terms and definitions apply to this part of GB/T 4854, 3.1
Air conduction conduction
The conduction of sound from the outer ear and middle ear to the inner ear. 3.2
Acoustic coupling cavityacousticcouplcr
It has a specified shape and volume and is used to calibrate the pressure in the earphone. The pressure in the cavity is measured by a microphone connected to it and calibrated.
Note: The provisions of the acoustic coupling cavity can be found in GB/T7342. 3.3
artificial ear
A device for calibrating earphones, which makes the acoustic impedance of the earphones equivalent to the average acoustic impedance of the human ear. Note:
A calibrated microphone is installed in the real ear and is used to measure the positive sound produced by the earphone. T
2 The provisions of the artificial ear can be found in GR/T7614.
Threshold of hearing hearing
The lowest sound pressure level that the subjects can correctly perceive in 50% of repeated tests under specified conditions. 1) The new version is TFC60318-3.
2) The new version is IEC:60318-1..
GB/T 4854.1—2004/ISO 3B9-1:19983.5
otologically Bormal person A person with normal health, no ear disease symptoms, no ear canal blockage, no history of excessive noise exposure, no ear-repellent drugs or family hearing loss.
Equivalent threshod sound pressure level (monaural earphone listening) The sound pressure level produced by the earphone in a specified acoustic coupling cavity or a real ear when the specified type of earphone is placed on the human ear with a specified force, at a specified frequency, and with a voltage corresponding to the listening voltage. 3.7
reference equivalent threshold sound pressure level (RETSPL) The mode value of the equivalent sound pressure level of a sufficient number of normal male and female otologists aged 18 to 30 years at a specified frequency. Note: The relationship between air conduction hearing level and age is shown in GB/T7582.3.8
[Pure tone] Hearing level Hearing level (of a pure tone) At a specified frequency, for a specified type of headphones and a specified mode of use, the difference between the pure tone sound pressure level produced by the headphones in a specified acoustic coupling cavity or artificial ear and the corresponding reference equivalent threshold sound pressure level. 3.9
[Given ear] Hearing threshold level (of a given ear) At a specified frequency, for a specified type of headphones, the hearing level of a certain ear expressed in hearing level. Note: For examples of suitable test conditions, see GB/T7583 or GB/T16403. 4 Technical requirements
4.1 Overview
The reference equivalent sound pressure level (RETSPL) depends on the type of earphone and the type of acoustic coupling cavity with which the calibrated earphone is mounted. 4.2 Beyer DT48 and Telephonics TDH39 earphones For these two different earphones, in a coupling cavity that complies with the provisions of GB/T7342, the recommended reference equivalent threshold acoustic level is shown in Table 1. When Beyur DT 48 earphones are placed in the human ear, they should be equipped with flat ear pads; when placed in a coupling cavity, an adapter 3 should be used to replace the ear pads. When TDH39 earphones are placed in the human ear and coupling cavity, they should be equipped with MX41/AR (or 51 type) ear pads. When the earphones act on the coupling cavity, they should be subjected to a nominal static force of (4.5 ± 0.5) N (excluding the weight of the earphones) to ensure that there is no leakage. Table 1 Recommended values of reference equivalent sound pressure level in a sound cavity in accordance with GB/T 7342 Frequency/Hz
3] For the provisions on adapters, see reference [1]. Reference equivalent sound pressure level/dB (reference sound pressure; 20 μPa) 47.5
Frequency/Hz
Headphone model
Table continued
GB/T 4854.1--2004/SO 389-1:1998 Reference equivalent sound pressure level/dR (reference pressure: 20 μPa) 1t.5
Bcycr IY1 48 With flat ear pads
Telephonics TDH 3y' With MX41/AR (or 51 type) ear pads
aThe filter cloth of the Telephanics TDH 39 headphones was changed in 1963 to match the 9A paste to produce the same headphone response. During this period, about 1000 pairs of headphones with unmatched filter cloth were produced. The data given in this section are the average values of a number of flat earphones manufactured before and after 1963. Note: The values in the table are adjusted to C.5 dB.
4.3 Other supra-aural headphones
For supra-aural headphones in artificial ears that comply with GB/T7614, the recommended reference equivalent output pressure levels are shown in Table 2. These values apply to headphones that meet the following requirements (to avoid uncertainties that may arise from other reasons, the headphone models specified in 4.2 are not included): a) The headphone and its ear pad (if available) should be axially symmetrical; the structure and material should provide a good acoustic seal between the headphone (or its ear pad) and the human ear; b) When the ear is placed on a flat surface, the diameter of the circumference of the contact surface of the headphone (or its ear pad) is equivalent to the long diameter of the human ear fan; d) No part of the headphone (or its ear pad) shall protrude beyond the contact surface given in c), and its top should be close to the shape of a truncated cone; The effective diameter of the contour line of the headphone or its ear pad (if available) in contact with the artificial ear specified in GB/T 7614 is only 25 mm: Note: This requirement means that the diameter exceeds 25 mm The cone angle of the earphone contour line tangent to any chain body will be greater than 116°) If there are ear pads, the material used should not be too soft to avoid obvious deformation of the machine when tested on the simulated ear: when the static force changes from 5N to 10N, the change in the sensitivity level measured at 1kHz should not be greater than 0.2dB, g)
When the earphone or its ear pad (if available) is placed on the human ear 1, its contour should be in contact with the auricle, but not with the head tissue behind the auricle:
Note: This requirement does not include over-ear headphones, 1) The headband used should be able to apply a static force of (4.5±0.5)N to the ear. The reference equivalent acoustic level applies when the earphone is coupled to a real ear under the following conditions:
The earphone is coaxial with the artificial ear and the axis is perpendicular to the ground; GB/T4854.1-2004/IS0389-1:1998 No sound leakage;
wUse (4.5 ± 0.5)N nominal static force excluding the weight of the earphone Table 2 Reference equivalent acoustic sound pressure level in an artificial ear that complies with GB/T 7614 Frequency/Hz
Note: The values in the table have been rounded to 0.5 dB. Reference equivalent acoustic sound pressure level/dB (reference sound pressure: 20 μPa) 45
At Derived
A, 1.1 Overview
Appendix A
【Informative Appendix】www.bzxz.net
GB/T4854.1—2004/IS0 389-1:1998 Derivation and application of recommended reference levels It should be emphasized that it can be accurately determined from the existing data that the reference equivalent threshold sound pressure levels given in Tables 1 and 2 refer to the same listening instantaneous level. The difference between them is mainly due to the acoustic characteristics between the coupling chamber and the artificial ear. A. 1. 2-octave frequency and additional audiometric frequencies 1500 Hz, 3 000 Hz and 6 000 Hz The reference equivalent sound pressure levels of the Beyer D148 re-instrument given in Table 1 are consistent with the average of 15 test results published between 1950 and 1961 (or other data obtained by ISO). These data were determined by the following 5 standardization laboratories through cooperative research. They are: France Telecom National Research Center, German Institute of Physics of Technology, UK National Physical Laboratory, US National Bureau of Standards and (former) Soviet Union All-Union Metrology Research Laboratory.
The reference equivalent loudsound pressure level of Telephonics TDH 39 headphones given in Table 1 was obtained later using the subjective loudness balance method. See references [2~5] for details.
The reference equivalent loudsound pressure level given in Table 2 is the average of the results of several samples of 6 types of headphones. This is done by the following laboratories, using alternating electrical excitations on the headphones to compare the sound pressure levels generated in the coupling cavity (see GB/T7342) and the artificial ear (see GB/T7614).
The experiments involved are: Naveen Hearing Institute, Swedish Rolinska Institute, US National Standards Agency, UK National Physical Laboratory and German Institute of Physics of Technology. See reference [6] for details. A.1.3 Supplementary frequencies
The reference equivalent threshold sound pressure levels at the supplementary frequencies are derived by interpolation of the values of the specified octave band frequencies and the adjacent audiometric frequencies 1500 Hz, 300) Hz and 6000 Hz and are supported by some experimental data. In the frequency range (125 to 1000) Hz, the interpolation is based on the assumption of a cubic polynomial relationship between the reference level (dB) and 1 g (F). In the frequency range (1 000 to 8 000) Hz, linear interpolation is used for Table 1. For Table 2, linear interpolation is used for the frequency range (1 000 to 4 000) Hz and frequencies above 4 000 Hz are obtained from experimental data. Note: The following laboratories provided experimental data for this standard: Taiwa Health and Welfare Laboratory, Canada, Institute of Physics and Technology, Germany, Swedish Regional Management Station and Technical University of Denmark. For details, see reference [?~10] A.2 Application
A.2.1 For audiometer calibration with a type of earphone mentioned in Table 1 or specified in 4.3, the acoustic output of the earphone shall be measured at the reference equivalent sound pressure level recommended in the corresponding table using a coupler or artificial ear of the specified type. When the earphone is worn on the ear, the headband used shall provide a nominal static force of 4.5 N = 0.5 N. Note that for an average head width of 145 mm, the headband force is 4.5 N. For adult subjects, this difference is usually observed. A.2.2 For earphones of the type used for audiometry that are neither mentioned in Table 1 nor specified in 4.3, the reference equivalent threshold sound pressure level appropriate for the type of earphone shall first be determined. Appropriate "equal loudness balance" or "audio-visual balance" techniques shall usually be used. Subjective comparison of the earphone with one of the earphones discussed in Chapter 1 shall be made. In some cases, the results of this comparison may already be applied. For detailed experimental equipment and technical process for this work, please consult the manufacturer or directly the laboratory responsible for setting the standards. GB/T 4854.1—2004/ISO 389-1: 1998 Reference
1J Mrass H, and Diestel H, G. Acoustica 1959, 9: 61-64E2] Weissler PG International Standard Reference Zero for Audiometers, J. Acoust, Soc. Arner, ,1968;44:264-275||tt ||E3] Cox Jr, JR and Bilger RC Suggestion Relative to the Standardization of Ioudness-Halance data for the Telephonics TDH-39 Earphone. J. Acoust. Soc. Amer. + 1960, 32: 1081-1082[4]J Whittle L, S. and Delany M E. Equivalent threshold sund-pressure levels for the TDH-39/MX41-AR Earphone. J. Acoust. Suc.Amer.:1966, 39: 1187-1188E5 Michael PL and Bienvenue GR A comparison of acoustical performance between a Ilew one-piect earphone cushion and the conventional two-pieceMX-4i/AR cushion.J.Acoust.Soc.A-mer.1980;67(2):693-698
E6] Robinson D , W. A proposal for Audiometric zero referred to the [EC artificial ear. UK NationalPhysical Laboratory.Acoustics Report Ac 85 (1978)F7J Arlinger S. Normal thresholds of hearing at preferred frequencies. Scand. Audiol. , 1982, 1l :285-286
[8] Rasrnussen O, Reference equivaleni. threshold sound pressurc levels for headphones at one-thitdoctave standard frequencies. Internal Repart No. 14, 1981. The Acoustic Lahoratory, TechnicalUniversity of Denmark,Lyngby
[gJ Brinkmann K. and Richter U. Determinatian of the normal threshold of hearing by bone conduction using different types of bone vibrators. Audiological Acoustics, 1983; 22: 62-85, 1l14 122EloJ Benwell DA and Hussey RG Rcf crence cquivalent threshold sound pressure levels at 5 and6. 3 kHz using Telephonits TDH 39 earphones with MX-4l/AR cushions, J. Acoust, Soc, A-mer..72, 1982, Supplement 1, p. S. 109111GB/T3240-1982 Common frequencies in acoustic measurements 12GB/T7583-1987 Acoustic pure tone air conduction audiometry for hearing protection 13]GB/T7582-2004 Statistical distribution of acoustic hearing and age relationship [14]GB/T4854.3-1998 Acoustic calibration of audiometric equipment - Reference zero level - Part 3: Bone vibrator pure tone fundamental equivalent threshold force level [15] GB/T 16403-1996 Acoustic audiometry methods - Basic audiometry for pure tone air conduction and bone conduction
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