IEC PAS 62459:2006

Sound system equipment - Electroacoustical transducers - Dynamic measurement of suspension parts

applies to the suspension parts of electroacoustical transducers (for example, loudspeakers). It defines the parameters and measurement method to determine the stiffness of suspension parts like spiders, surrounds, diaphragms or cones before being assembled in the transducer. The measurement results are needed for engineering design purposes and for quality control. Furthermore, this method is intended to improve the correlation of measurements between suspension-part manufacturers and loudspeaker manufacturers

General Information

• Status: Replaced
• Publication Date: 24-Jan-2006
• ICS: 33.160.50 - Accessories
• Technical Committee: TC 100 - Audio, video and multimedia systems and equipment
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 27-Jan-2010

Relations

• Replaced By: IEC 62459:2010 - Sound system equipment - Electroacoustical transducers - Measurement of suspension parts
• Effective Date: 05-Sep-2023
• Corrected By: IEC 62459:2010/COR1:2015 - Corrigendum 1 - Sound system equipment - Electroacoustical transducers - Measurement of suspension parts
• Effective Date: 05-Sep-2023

Standards Content (Sample)

PUBLICLY
IEC
AVAILABLE
PAS 62459
SPECIFICATION
First edition
Pre-Standard
2006-01
Sound system equipment –
Electroacoustical transducers –
Dynamic measurement of suspension parts

Reference number
IEC/PAS 62459:2006(E)
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PUBLICLY
IEC
AVAILABLE
PAS 62459
SPECIFICATION
First edition
Pre-Standard
2006-01
Sound system equipment –
Electroacoustical transducers –
Dynamic measurement of suspension parts

 IEC 2006  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale
M
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – PAS 62459 © IEC:2006(E)
CONTENTS
FOREWORD.3

INTRODUCTION.5

1 Scope .6

2 Terms and definitions.6

3 Test equipment.7

4 Test method .8

5 Test result .8

Annex A (informative) Code of practice .10
Bibliography .13

PAS 62459 © IEC:2006(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
SOUND SYSTEM EQUIPMENT –
Electroacoustical transducers –

Dynamic measurement of suspension parts

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
A PAS is a technical specification not fulfilling the requirements for a standard but made
available to the public.
IEC-PAS 62459 has been processed by IEC technical committee 100: Audio, video and
multimedia systems and equipment.
The text of this PAS is based on the This PAS was approved for
following document: publication by the P-members of the
committee concerned as indicated in
the following document
Draft PAS Report on voting
100/999/NP 100/1059/RVN
Following publication of this PAS, which is a pre-standard publication, the technical committee
or subcommittee concerned will transform it into an International Standard.
This PAS shall remain valid for an initial maximum period of three years starting from
2006-02. The validity may be extended for a single three-year period, following which it shall
be revised to become another type of normative document or shall be withdrawn.

– 4 – PAS 62459 © IEC:2006(E)
INTRODUCTION
A ready-to-use loudspeaker is the result of international division of labour. An important role

is played by the suspension parts which must have reproducible behaviour for the

manufacturing of equipment. This document gives a measurement method and parameters for

the quality-assurance applications by suspension-part manufacturers and loudspeaker

manufacturers.
The lowest resonance frequency of an electroacoustical transducer (for example, a

loudspeaker) depends on the mechanical stiffness and the mass of the moving components.

These elements include the mass of the diaphragm or cone, the mass of the voice coil, the

mass of the air load, the stiffness of the spider and the stiffness of the surround and, if
applicable, the stiffness of the air in the loudspeaker enclosure. Whereas the moving mass
may be assumed as constant, the stiffness depends on the instantaneous voice coil position x,
humidity, temperature and reversible and non-reversible changes versus time. The break-in
effect of a new spider and natural ageing are examples of non-reversible processes. A
reversible process is the reduction of the stiffness, K(x = 0), at the rest position, x = 0, after
performing a large excursion and the restoration of the original stiffness at K(x = 0) after a few
seconds. Closely related is the creep effect and the dependency of the stiffness, K(f), on the
frequency of a sinusoidal stimulus. The visco-elastic behaviour causes a discrepancy between
the stiffness measured statically and dynamically. The results of a dynamic measurement
technique are more relevant for the final application of suspension parts at audio frequencies.

PAS 62459 © IEC:2006(E) – 5 –
SOUND SYSTEM EQUIPMENT –
Electroacoustical transducers –

Dynamic measurement of suspension parts

1 Scope
This PAS applies to the suspension parts of electroacoustical transducers (for example,
loudspeakers). It defines the parameters and measurement method to determine the stiffness

of suspension parts like spiders, surrounds, diaphragms or cones before being assembled in

the transducer. The measurement results are needed for engineering design purposes and for

quality control. Furthermore, this method is intended to improve the correlation of
measurements between suspension-part manufacturers and loudspeaker manufacturers.
The measurement method provides the effective stiffness, K based on a linear model and
eff,
the variation of the stiffness, K(x), versus displacement x using a non-linear model. Both
parameters are measured dynamically by exciting the suspension part to mechanical
vibrations.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
inner clamp dimension, D
I
diameter at the neck of the suspension part which is clamped by inner clamping parts (for
example, cone and cup)
2.2
outer clamp dimension, D
o
inner diameter of the outer rim of the suspension part which is clamped by the outer clamping
parts (for example, the upper and lower clamping rings)
2.3
displacement, x
displacement measured in the perpendicular direction at the inner rim of the suspension part
2.4
driving force, F
force representing the total effect of the restoring force, friction and inertia of both the

suspension part and the inner clamping parts at the neck of the suspension
2.5
transfer function, H(f)
function defined as the amplitude response
Xj()ω
Hf()=     (1)
F()jω
between the displacement spectrum X(jω) = FT{x(t)} and the force spectrum F(jω) = FT{F(t)}
2.6
resonance frequency, f
R
frequency at which the restoring force, F = K(x)x, equals the inertia at the moving mass, m
K
– 6 – PAS 62459 © IEC:2006(E)
2.7
moving mass m
mass defined as
(2)
mm=δ +m
sc
where
m is the mass of the suspension part;

s
m is the additional mass of the inner clamping parts;
c
δ is the clamping factor (with 0 < δ ≤ 1) describing the fraction of the suspension which
contributes to the moving mass. If factor δ is not known, the moving mass is
approximated by using the total weight of the suspension part (δ =1) and ensuring that
the mass, m , of the inner clamping part dominates the moving mass, m (m >> m )
c c s
2.8
effective stiffness, K
eff
stiffness defined as
(3)
K()Xf=()2πm
eff peak R
describing the conservative properties of the suspension part performing a vibration at the
resonance frequency, f , using the moving mass, m
R
2.9
non-linear stiffness, K(x)
stiffness describing the dependency of the stiffness on voice coil displacement, x, while
performing a vibration at the resonance frequency, f
R
2.10
loss factor, Q
factor estimated as the ratio
H()f
R
Q= (4)
H()f
between the magnitude of the transfer function, H(f ), at resonance frequency, f , and the
R R
magnitude of the transfer function, H(f ), at very low frequencies, f (with f << f ). If the losses
0 0 0 r
are sufficiently high (Q > 2), the transfer function, H(f), has a distinct maximum (peak) at the
resonance frequency, f
R
2.11
peak displacement, X
peak
peak value of the displacement occurring during the measurement at the resonance frequency,
f
R
3 Test equipment
The essential elements of the test equipment needed are as follows:
– a sine wave generator and frequency counter;
– means for exciting the suspension part (for example, pneumatically);
– outer clamping parts (for example, a pair of matched clamping rings);
– inner clamping parts (for example, a cone and a cup);

PAS 62459 © IEC:2006(E) – 7 –
– means for determining the displacement and force at the suspension part by performing a

direct (mechanical) or indirect (acoustical) measurement.

4 Test method
Both the effective stiffness, K and the displacement varying stiffness, K(x), of the
eff,
suspension part are measured dynamically by performing the following ste
...