This part of IEC 60118 gives recommendations for the measurement of the performance characteristics of air conduction hearing aids based on a free field technique and measured with an acoustic coupler.

This part of IEC 60118 is applicable to the measurement and evaluation of the electroacoustical characteristics of hearing aids, for example for type testing and manufacturer data sheets.

The test results obtained by the methods specified in this part of IEC 60118 will express the performance under conditions of the test and may deviate substantially from the performance of the hearing aid under actual conditions of use.

This part of IEC 60118 uses an acoustic coupler according to IEC 60318‑5 which is only intended for loading a hearing aid with a specified acoustic impedance and is not intended to model the sound pressure in a person’s ear. The use of this acoustic coupler will yield different results from those obtained using the occluded ear simulator of IEC 60318‑4 as used in former editions of IEC 60118‑0 .

For the measurement of the performance characteristics of hearing aids for simulated in situ working conditions, IEC 60118‑8 can be used. For measurement of hearing aids under typical user settings and using a speech-like signal, IEC 60118‑15 can be used.

For the measurement of the performance characteristics of hearing aids for production, supply and delivery quality-assurance purposes, IEC 60118‑7 can be used. The frequency range has been extended to 8 kHz in this part of IEC 60118 as opposed to 5 kHz in IEC 60118‑7 .

Though the number of measurements covered by this part of IEC 60118 is limited, it is not intended that all measurements described herein are mandatory.

In cases of custom-made in-the-ear instruments, the data supplied by the manufacturer applies only to the particular hearing aid being tested.

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PDF Pages	PDF Title
6	English CONTENTS
9	FOREWORD
11	1 Scope 2 Normative references
12	3 Terms and definitions
16	4 General conditions 4.1 Acoustic test method
17	4.2 Acoustic coupler 4.3 Measurement frequency range 4.4 Reporting of data 5 Test enclosure and test equipment 5.1 General 5.2 Unwanted stimuli in the test enclosure 5.3 Sound source
18	5.4 Measurement system for the measurement of the sound pressure level and harmonic distortion produced by a hearing aid 5.5 Direct-current measuring system
19	5.6 Magnetic field source for ETLS and MASL measurements 6 Test conditions 6.1 General
20	6.2 Control of the sound field Figures Figure 1 – Example of test arrangement for behind-the-ear hearing aid
21	6.3 Measurement configuration for directional hearing aids Figure 2 – Example of test arrangement for in-the-ear hearing aid
22	6.4 Normal operating conditions for a hearing aid 6.4.1 General 6.4.2 Battery or supply voltage Figure 3 – Example of test arrangement for directional hearing aid
23	6.4.3 Settings of controls 6.4.4 Ambient conditions 6.4.5 Sound outlet system Tables Table 1 – Resistors and open circuit voltages for zinc-air battery simulators
24	6.4.6 Accessories 7 Test procedures 7.1 Frequency response curves 7.2 OSPL90 frequency response curve
25	7.3 Full-on gain response curve 7.4 Basic frequency response curve 7.4.1 Test procedure Figure 4 – Example of OSPL90 curve and basic frequency response curve
26	7.4.2 Frequency range Figure 5 – Example of determination of frequency rangefrom basic frequency response curve
27	7.4.3 Reference test gain (RTG) 7.5 Total harmonic distortion 7.6 Equivalent input noise 7.7 Battery current Table 2 – Distortion test frequencies and input sound pressure levels
28	7.8 Measurements for hearing aids having induction pick-up coil 7.8.1 General 7.8.2 Equivalent test loop sensitivity (ETLS) 7.8.3 Maximum HFA magneto-acoustical sensitivity level (HFA MASL) of induction pick-up coil 8 Characteristics of electrical input circuits for hearing aids 8.1 Electrical characteristics 8.1.1 General
29	8.1.2 Input impedance 8.1.3 Input sensitivity 8.2 Mechanical characteristics and electrical function of connector system for electrical input 9 Additional optional test procedures 9.1 General 9.2 Effects of tone control and gain control 9.2.1 Basic frequency response: effect of tone control 9.2.2 Frequency response: effect of gain control position
30	9.2.3 Characteristics of the gain control 9.3 Intermodulation distortion 9.4 Effects of variation of battery or supply voltage and internal resistance 9.4.1 Full-on gain
31	9.4.2 OSPL90 9.4.3 Total harmonic distortion 9.4.4 Total intermodulation distortion 9.5 Equivalent input noise in one-third-octave bands
32	Figure 6 – Example of hearing aid acoustic gain
33	Figure 7 – Example of hearing aid output noise and test equipment noise Figure 8 – Hearing aid equivalent input noise and ambient noise
34	9.6 Additional measurements for hearing aids having induction pick-up coil 9.6.1 General 9.6.2 Basic frequency response 9.6.3 Frequency response with full-on gain control setting 9.6.4 Effect of gain control position on frequency response
35	9.6.5 Harmonic distortion 9.7 Additional measurements for hearing aids having induction pick-up coil for use with a telephone 9.7.1 General Figure 9 – Telephone magnetic field simulator (TMFS)
36	9.7.2 SPLITS response curve 9.7.3 HFA-SPLITS 9.7.4 Relative simulated equivalent telephone sensitivity (RSETS) Figure 10 – Example of hearing aids on TMFS for SPLITS test
37	9.8 Additional measurements applying to AGC hearing aids 9.8.1 General 9.8.2 Steady-state input-output characteristics Figure 11 – Example of a steady-state input-output characteristic
38	9.8.3 Dynamic AGC characteristics (attack and release time) 9.9 Additional optional measurements with ear simulator, according to IEC 60318-4 9.9.1 General 9.9.2 Output sound pressure level frequency response curve for an input sound pressure level of 90 dB 9.9.3 Full-on gain response curve 9.9.4 Basic frequency response curve 9.9.5 Presentation of data 10 Maximum permitted expanded uncertainty of measurements
39	Table 3 – Values of Umax for basic measurements
40	Bibliography

Status	Withdrawn
Title	Electroacoustics. Hearing aids – Measurement of the performance characteristics of hearing aids
Replaces	BS EN 60118-2:1996, BS EN 60118-6:1999 (Edition 2), BS EN 60118-0:1993, BS EN 60118-1:1995
Publisher	BSI
Committee	EPL/29
Pages	42
Publication Date	2015-09-30
Withdrawn Date	2024-05-16
Replaced By	BS EN IEC 60118-0:2024
ISBN	978 0 580 76794 4
Standard Number	BS EN 60118-0:2015
Identical National Standard Of	IEC 60118-0:2015, EN 60118-0:2015
Descriptors	Acoustoelectric devices, Sound intensity, Acoustic measurement, Aids for the disabled, Hearing aids, Medical equipment, Definitions, Electrical measurement, Testing conditions, Frequency response, Performance testing
ICS Codes	17.140.50 - Electroacoustics


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