IEC TS 60318-7:2011

IEC/TS 60318-7 ®
Edition 1.0 2011-02
TECHNICAL
SPECIFICATION
Electroacoustics – Simulators of human head and ear –
Part 7: Head and torso simulator for the measurement of hearing aids

IEC/TS 60318-7:2011(E)
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IEC/TS 60318-7 ®
Edition 1.0 2011-02
TECHNICAL
SPECIFICATION
Electroacoustics – Simulators of human head and ear –
Part 7: Head and torso simulator for the measurement of hearing aids

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
V
ICS 17.140.50 ISBN 978-2-88912-379-7
– 2 – TS 60318-7  IEC:2011(E)
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Construction . 11
4.1 General . 11
4.2 Geometrical dimensions of the manikin . 11
4.2.1 Torso . 11
4.2.2 Head . 18
4.2.3 Pinna . 24
4.2.4 Ear simulator . 28
4.2.5 Materials . 29
4.2.6 Markings . 29
4.2.7 Tolerances . 29
4.3 Acoustical characteristics of the manikin . 29
4.3.1 Free field frequency response . 29
4.3.2 Tolerances . 29
4.3.3 Openings . 30
5 Calibration . 30
5.1 Atmospheric reference conditions . 30
5.2 Calibration method . 30
5.2.1 General . 30
5.2.2 Test space and measurement equipment . 30
5.2.3 Measurement of sound pressure level . 31
5.2.4 Alignment of manikin azimuth and elevation . 31
5.2.5 Test for sound leakage . 31
6 Maximum permitted expanded uncertainty of measurements . 32
Annex A (informative) Ear canal sound pressure ratio . 34
Bibliography . 35

Figure 1 – Manikin geometrical references . 9
Figure 2 – Coordinate scheme for azimuth and elevation angles . 10
Figure 3 – Illustration of manikin head and torso dimensions . 12
Figure 4 – Cross-sections of torso (tolerance ± 4 mm) . 17
Figure 5 – Cross-sections of head (tolerance ± 2,5 mm) . 23
Figure 6 – Illustration of manikin pinna dimensions . 24
Figure 7 – Cross-sections of right pinna (tolerance ± 1,5 mm) . 28

Table 1 – Head and torso dimensions for the manikin and average human data . 12
Table 2 – Pinna dimensions for the manikin . 24
Table 3 – Free field frequency response of the manikin . 32
Table 4 – Values of U for basic measurements . 33
max
Table A.1 – Ear canal sound pressure ratio . 34

TS 60318-7  IEC:2011(E) – 3 –

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROACOUSTICS –
SIMULATORS OF HUMAN HEAD AND EAR –

Part 7: Head and torso simulator
for the measurement of hearing aids

FOREWORD
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The main task of IEC technical committees is to prepare International Standards. In
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specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC/TS 60318-7, which is a technical specification, has been prepared by IEC technical
committee 29: Electroacoustics.

– 4 – TS 60318-7  IEC:2011(E)
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
29/716/DTS 29/729A/RVC
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60318 series, published under the general title Electroacoustics –
Simulators of human head and ear, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this document may be issued at a later date.

TS 60318-7  IEC:2011(E) – 5 –
INTRODUCTION
This technical specification describes a head and torso simulator for hearing aid
measurements. It has been developed as a revision of IEC/TR 60959 (1990). The main
changes, as compared to the technical report, are the insertion of maximum permitted
expanded measurement uncertainties and additional references in the Bibliography. A future
IEC Standard which will include additional models of head and torso simulators for hearing aid
measurements is planned.
– 6 – TS 60318-7  IEC:2011(E)
ELECTROACOUSTICS –
SIMULATORS OF HUMAN HEAD AND EAR –

Part 7: Head and torso simulator
for the measurement of hearing aids

1 Scope
This part of IEC 60318 describes a head and torso simulator (manikin) intended for the
measurement of air-conduction hearing aids in the frequency range from 100 Hz to 10 000 Hz.
The device consists of a head mounted on a torso that extends to the waist. The head is
equipped with simulated pinnae and with cylindrical cavities having acoustic impedance
terminations and microphones located at positions corresponding to those of the eardrums in
a median human adult. It has been designed to provide acoustic diffraction similar to that
encountered around the median human head and torso.
The device with its present pinna simulator, however, is not suitable for the measurement of
all types of hearing aids. For example, most in-the-ear (ITE) and completely-in-the-canal
(CIC) hearing aids cannot be measured correctly.
The manikin is specified in terms of both, its geometrical dimensions and its acoustical
properties.
NOTE 1 Measurement results obtained with a manikin may differ substantially from similar results obtained on an
individual person, due to anatomical variations.
NOTE 2 The median values of the human head and torso were drawn from the population samples described
in [5] .
NOTE 3 It is acknowledged that devices conforming to this part of IEC 60318 are also used as the basis for
applications extending beyond this Scope. In such cases it is recommended that any design variations that are
necessary are documented, and that a statistical analysis of the measurement data be carried out to determine the
level of repeatability that can be achieved. It will also be necessary to consider the relevance of the measurements
made with the head and torso simulator to the application in question.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60318-4, Simulators of human head and ear – Part 4: Occluded-ear simulator for the
measurement of earphones coupled to the ear by means of ear inserts
ISO/IEC Guide 98-3, Uncertainty of measurement – Part 3: Guide to the expression of
uncertainty in measurement (GUM:1995)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. Reference is
also made to Figure 1 and Figure 2.
———————
Numbers in square brackets refer to the Bibliography.

TS 60318-7  IEC:2011(E) – 7 –
3.1
manikin
head and torso simulator extending downward from the top of the head to the waist and
designed to simulate the acoustic diffraction produced by a median adult human head and
torso
NOTE The head includes two pinna simulators, and contains at least one ear simulator.
3.2
pinna simulator
device which has the approximate shape and dimensions of a median adult human pinna
3.3
ear simulator
device for measuring the acoustic output of sound sources where the sound pressure is
measured by a calibrated microphone coupled to the source so that the overall acoustic
impedance of the device approximates that of the normal human ear at a given location and in
a given frequency band
NOTE In this technical specification it comprises an ear canal extension and an occluded ear simulator.
3.4
occluded ear simulator
ear simulator which approximates the acoustic transfer impedance of the inner part of the ear
canal, from the tip of an ear insert to the eardrum
NOTE An occluded ear simulator is standardised in IEC 60318-4.
3.5
ear canal extension
device that provides a connection between the ear canal of an occluded ear simulator and the
aperture of a device simulating the concha
3.6
reference plane of the occluded ear simulator
plane perpendicular to the axis of the ear canal, at the junction between the occluded ear
simulator and the ear canal extension
3.7
reference point of the manikin
point bisecting the line joining the centres of the openings of the ear canals (at the junction
between concha and ear canal)
3.8
plane of symmetry of the manikin
virtual plane passing through the reference point of the manikin that divides the left and right
portions of the manikin into symmetrical halves, left and right to be interpreted as for the
human torso (see Figure 1)
NOTE No real human is perfectly symmetrical.
3.9
axis of rotation of the manikin
straight line about which the manikin can be rotated, passing through the reference point of
the manikin and lying in the plane of symmetry of the manikin, and having a direction that
would be vertical if the manikin were mounted in a position corresponding to that of a standing
person (see Figure 1)
– 8 – TS 60318-7  IEC:2011(E)
3.10
reference plane of the manikin
plane perpendicular to the axis of rotation that contains the reference point of the manikin
3.11
test point
reproducible position in the test space at which the sound pressure level is measured with the
manikin absent and at which the reference point of the manikin is to be located for test
purposes
3.12
test axis
line joining the test point and the centre of the sound source (see Figure 2)
3.13
test plane
plane perpendicular to the test axis and containing the test point
3.14
azimuth angle of sound incidence
θ
angle between the plane of symmetry of the manikin (see Figure 2) and the plane defined by
the axis of rotation and the test axis; when the manikin faces the sound source, the azimuth
angle of sound incidence is defined as 0°
NOTE When the right ear of the manikin faces the sound source, the angle is defined as +90°. When the left ear
of the manikin faces the sound source, the angle is defined as +270°.
3.15
elevation angle of sound incidence
α
angle between the reference plane of the manikin and the test axis (see Figure 2); when the
vertex points towards the sound source, the elevation angle is defined as +90°
NOTE When the test axis lies in the reference plane, the elevation angle is defined as 0°.

TS 60318-7  IEC:2011(E) – 9 –

Vertex Vertex
Axis of rotation
Reference plane of the manikin
90°
90°
Reference point
Axis of rotation and
plane of symmetry
Reference point (and top view of axis
of rotation). It bisects the line joining
the centres of the openings of the
ear simulator canals
90°
IEC  398/11
NOTE The reference point is the reference point of the manikin.
Figure 1 – Manikin geometrical references

– 10 – TS 60318-7  IEC:2011(E)

Test axis
Elevation angle of sound incidence
α
Range: –90° to +90°
Reference plane
Reference point and
test point
Azimuth angle of sound incidence
θ
Range: 0° to +360°
Test axis
Sound source
Reference point and
test point
IEC  399/11
NOTE The reference point is the reference point of the manikin.
Figure 2 – Coordinate scheme for azimuth and elevation angles

TS 60318-7  IEC:2011(E) – 11 –
3.16
reference position of the manikin
position of the manikin in the test space that meets the following conditions:
– the reference point of the manikin coincides with the test point,
– the azimuth and elevation angles are both equal to zero
3.17
manikin free field frequency response
difference, as a function of frequency, between the sound pressure level at the ear simulator
microphone with the reference point of the manikin at the test point and the sound pressure
level at the test point with the manikin absent
3.18
ear canal entrance point
EEP
point located at the centre of the manikin ear canal at the junction between concha and ear
canal extension
3.19
vertical pinna reference axis
line through the EEP, and parallel to the axis of rotation of the manikin
3.20
horizontal pinna reference axis
line through the EEP, and parallel to the reference plane of the manikin with an azimuth angle
of 90°
NOTE The horizontal pinna reference axis is needed for vertical cross-sections of a pinna simulator, see for
instance IEC 60268-7 [1].
4 Construction
4.1 General
In the following, both the geometrical physical dimensions of the manikin’s head, torso and
pinnae and the manikin’s acoustical characteristics are specified. Where tolerances are
specified in this technical specification, these shall be reduced by an amount equal to the
actual expanded measurement uncertainty of the test laboratory before deciding if a device
conforms to the stated requirement.
4.2 Geometrical dimensions of the manikin
4.2.1 Torso
4.2.1.1 The principal geometrical dimensions of the manikin torso are illustrated in Figure 3,
and listed in Table 1 (for information only). The realization of the torso is specified in 4.2.1.2.

– 12 – TS 60318-7  IEC:2011(E)

Head breadth Head length
Tragion to occipital wall
Head
height
Chin-to-vertex
length
Tragion to
Neck diameter shoulder
Bitragion diameter
Shoulder depth
Shoulder breadth
Chest depth
Chest breadth
Shoulder position
IEC  400/11 IEC  401/11
a) Front view b) Side view
NOTE For position of tragion, see Figure 6.
Figure 3 – Illustration of manikin head and torso dimensions
Table 1 – Head and torso dimensions for the manikin and average human data
Dimension Manikin Average human data [5]
(mm) (mm)
Head breadth 152 151
Head length 191 188
Head height (tragion to vertex) 125 130
Bitragion diameter 143 139
Tragion t
...