Recommendation ITU-T P.57 (06/2021) Artificial ears
Summary
History
FOREWORD
Table of Contents
1 Scope and object
     1.1 Scope
     1.2 Object
2 References
3 Definitions
     3.1 Terms defined elsewhere
     3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 Conventions
6 Artificial ear types
     6.1 Type 1 artificial ear
     6.2 Type 2 artificial ear
     6.3 Type 3 artificial ear
          6.3.1 Type 3.1 – Concha bottom simulator
          6.3.2 Type 3.2 – Simplified pinna simulator
          6.3.3 Type 3.3 – Pinna simulator
          6.3.4 Type 3.4 – Pinna simulator (simplified)
     6.4 Type 4 artificial ear
          6.4.1 Type 4.1 ear simulator
          6.4.2 Type 4.2 ear simulator
          6.4.3 Type 4.3 ear simulator
               6.4.3.1 Overview
               6.4.3.2 Ear-drum reference point to ear reference point correction
               6.4.3.3 Transfer impedance
               6.4.3.4 Geometry of the ear simulator
                    6.4.3.4.1 Overview
                    6.4.3.4.2 Coordinates of the centre line and the concha bottom
                    6.4.3.4.3 Unit vectors for each cross section of the ear canal
                    6.4.3.4.4 Cross sectional areas of the ear canal and concha bottom
                    6.4.3.4.5 Geometry of anatomically shaped pinna simulator
                    6.4.3.4.6 Coordinates of the EEP projections for the pinna simulator
                    6.4.3.4.7 Unit vector for the cross section of the pinna simulator
                    6.4.3.4.8 Cross sectional areas of the pinna simulator
          6.4.4 Type 4.4 ear simulator
               6.4.4.1 Overview
               6.4.4.2 Ear-drum reference point to ear reference point correction
               6.4.4.3 Transfer impedance
               6.4.4.4 Geometry of the ear simulator
                    6.4.4.4.1 Overview
                    6.4.4.4.2 Coordinates of the centre line and the concha bottom
                    6.4.4.4.3 Unit vectors for each cross section of the ear canal
                    6.4.4.4.4 Cross sectional areas of the ear canal and concha bottom
                    6.4.4.4.5 Geometry of anatomically shaped Pinna Simulator
                    6.4.4.4.6 Coordinates of the EEP projections
                    6.4.4.4.7 Unit vector for the cross section of the pinna simulator
                    6.4.4.4.8 Cross sectional areas of the pinna simulator
     6.5 Calibration of the artificial ears type 1 and type 3.2
          6.5.1 Performance testing of the IEC 60318-4 occluded-ear simulator (type 3.2 only)
          6.5.2 Frequency sensitivity response
          6.5.3 Acoustic input impedance
     6.6 Performance verification of the artificial ears types 2, 3.1, 3.3 and 3.4
     6.7 Atmospheric reference conditions
     6.8 General requirements
     6.9 Ear-drum reference point to ear reference point correction
7 Idle noise floor
Annex A  A practical procedure for determination of the acoustic input impedance of artificial ears
     A.1 Introduction
     A.2 Calibration of the impedance probe
          A.2.1 Frequency response of the probe microphone
          A.2.2 Relative frequency response of the transmitter microphone
          A.2.3 Absolute sensitivity of the transmitter microphone as a volume velocity source
     A.3 Artificial ear calibration
          A.3.1 Determination of acoustical impedance
          A.3.2 Determination of closed condition sound pressure sensitivity
Annex B  Cross sectional areas of type 4.3 artificial ear
     B.1 Cross sections of the concha bottom
     B.2 Cross sectional areas of the ear canal and concha bottom
     B.3 Cross sectional areas of the pinna simulator
Annex C  Cross sectional areas of Type 4.4 artificial ear
     C.1 Cross sections of the concha bottom
     C.2 Cross sectional areas of the ear canal and concha bottom
     C.3 Cross sectional areas of the pinna simulator
Appendix I  Comparative acoustical input impedance measurements on the artificial ears Types 3.3 and 3.4 and on human ears
     I.1  Introduction
     I.2  Data overview
     I.3 Artificial ear measurements
          I.3.1 HATS 3.3 ear
          I.3.2 HATS 3.4 ear
     I.4  Human ear measurements
          I.4.1 Univariate analysis of the human ear measurements
               I.4.1.1 Descriptive statistics
               I.4.1.2 Significance testing of experimental factors
          I.4.2 Bivariate parametric analysis of the human ear measurements
               I.4.2.1 Presentation of the analysis method
               I.4.2.2 Results of the parametric analysis
     I.5 Comparison between human and artificial ear measurements
          I.5.1 Univariate comparison of human and artificial ear measurements
          I.5.2 Bivariate parametric comparison of human and artificial ear measurements
          I.5.3 Comparison between human measurements and type 3.2 artificial ear measurements
          I.5.4 Identification of outliers from the box plot analysis
          I.5.5 Study of factor effects by univariate analysis of variance
Appendix II  Illustration of the mobile phone-shaped impedance probe used in Appendix I
Bibliography
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