Sound system equipment - Electroacoustic transducers - Measurement of large signal parameters

IEC 62458:2010(E) applies to transducers such as loudspeaker drive units, loudspeaker systems, headphones, micro-speakers, shakers and other actuators using either an electro-dynamical or electro-magnetic motor coupled with a mechanical suspension. The large signal behaviour of the transducer is modelled by a lumped parameter model considering dominant nonlinearities such as force factor, stiffness and inductance. It defines the basic terms and parameters of the model, the methods of measurements and the way the results should be reported. It cancels and replaces IEC/PAS 62458 published in 2006. It constitutes a technical revision. The main changes are: - descriptions of the methods of measurement are adjusted to the state of the technology; - addition of Clauses 4 to 15; - integration of Annex A in the main body of the standard; - overall textual review.

Elektroakustische Geräte - Elektroakustische Wandler - Messung von Großsignal-Parametern

Equipements pour systèmes électroacoustiques - Transducteurs électroacoustiques - Mesure des paramètres en grand signal

L'IEC 62458:2010 s'applique aux transducteurs tels que les unités motrices de haut-parleurs, les systèmes de haut-parleurs, les casques, les micro-haut-parleurs, les vibrateurs et autres actionneurs qui utilisent un moteur électrodynamique ou électromagnétique couplé à une suspension mécanique. Le comportement des signaux forts du transducteur est modélisé par un modèle de paramètres localisés qui tient compte des non-linéarités dominantes telles que le facteur de force, la rigidité et l'inductance, comme cela est représenté à la Figure 1. Cette norme définit les termes et paramètres de base du modèle, ainsi que les méthodes de mesurage et la manière dont il convient de consigner les résultats. L'IEC 62458:2010 annule et remplace l'IEC/PAS 62458 parue en 2006. Elle constitue une révision technique. Les principales modifications sont les suivantes: - la description des méthodes de mesurage a été adaptée à l'état de la technologie; - les Articles 4 à 15 ont été ajoutés; - l'Annexe A a été intégrée au corps de la norme; - le texte a été revu dans son intégralité.

Oprema zvokovnega sistema - Elektroakustični pretvorniki - Meritve parametrov velikih signalov (IEC 62458:2010)

Ta mednarodni standarda velja za pretvornike, kot so pogonske enote zvočnikov, sistemi zvočnikov, naglavne slušalke, mikrozvočniki, stresalniki in drugi aktivatorji, ki uporabljajo ali elektrodinamične ali elektromagnetne motorje, povezane z mehanskimi obesami. Vedenje velikih signalov pretvornikov je modelirano kot model ločenih parametrov ob upoštevanju dominantne nelinearnosti, kot so dejavnik sile, togost in induktivnost, prikazani na sliki 1. Ta standard določa osnovne izraze in parametre modela, metode merjenja in način, kako naj bodo rezultati prikazani.

General Information

Status
Published
Publication Date
24-Mar-2011
Current Stage
6060 - Document made available
Due Date
02-Apr-2011
Completion Date
25-Mar-2011

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SLOVENSKI STANDARD
SIST EN 62458:2011
01-julij-2011
2SUHPD]YRNRYQHJDVLVWHPD(OHNWURDNXVWLþQLSUHWYRUQLNL0HULWYHSDUDPHWURY
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Sound system equipment - Electroacoustic transducers - Measurement of large signal

parameters (IEC 62458:2010)
Elektroakustische Geräte - Elektroakustische Wandler - Messung von Großsignal-
Parametern (IEC 62458:2010)

Equipements pour systèmes électroacoustiques - Transducteurs électroacoustiques -

Mesure des paramètres en grand signal (CEI 62458:2010)
Ta slovenski standard je istoveten z: EN 62458:2011
ICS:
33.160.50 Pribor Accessories
SIST EN 62458:2011 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 62458:2011
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SIST EN 62458:2011
EUROPEAN STANDARD
EN 62458
NORME EUROPÉENNE
March 2011
EUROPÄISCHE NORM
ICS 33.160.50
English version
Sound system equipment -
Electroacoustic transducers -
Measurement of large signal parameters
(IEC 62458:2010)
Equipements pour systèmes Elektroakustische Geräte -
électroacoustiques - Elektroakustische Wandler -
Transducteurs électroacoustiques - Messung von Großsignal-Parametern
Mesure des paramètres en grand signal (IEC 62458:2010)
(CEI 62458:2010)

This European Standard was approved by CENELEC on 2011-01-02. CENELEC members are bound to comply

with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard

the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on

application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CENELEC member into its own language and notified

to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,

the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,

Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,

Spain, Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 62458:2011 E
---------------------- Page: 3 ----------------------
SIST EN 62458:2011
EN 62458:2011 - 2 -
Foreword

The text of document 100/1624/FDIS, future edition 1 of IEC 62458, prepared by IEC/TC 100, Audio,

video and multimedia systems and equipment, was submitted to the IEC-CENELEC parallel vote and was

approved by CENELEC as EN 62458 on 2011-01-02.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent

rights.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2011-10-02
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2014-01-02
Annex ZA has been added by CENELEC.
__________
Endorsement notice

The text of the International Standard IEC 62458:2010 was approved by CENELEC as a European

Standard without any modification.
__________
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SIST EN 62458:2011
- 3 - EN 62458:2011
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD

applies.
Publication Year Title EN/HD Year
IEC 60268-1 - Sound system equipment - HD 483.1 S2 -
Part 1: General
IEC 60268-5 2003 Sound system equipment - EN 60268-5 2003
A1 2007 Part 5: Loudspeakers A1 2009
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SIST EN 62458:2011
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SIST EN 62458:2011
IEC 62458
Edition 1.0 2010-01
INTERNATIONAL
STANDARD
colour
inside
Sound system equipment – Electroacoustical transducers – Measurement of
large signal parameters
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
ICS 33.160.50 ISBN 978-2-88910-733-9
® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 7 ----------------------
SIST EN 62458:2011
– 2 – 62458 © IEC:2010(E)
CONTENTS

FOREWORD...........................................................................................................................4

INTRODUCTION.....................................................................................................................6

1 Scope...............................................................................................................................7

2 Normative references .......................................................................................................7

3 Terms and definitions .......................................................................................................7

4 Test signals......................................................................................................................9

4.1 General ...................................................................................................................9

4.2 Large d.c. signal......................................................................................................9

4.3 Large d.c. signal and small a.c. signal.....................................................................9

4.4 Broadband noise signal ...........................................................................................9

4.5 Music ......................................................................................................................9

5 Mounting condition .........................................................................................................10

5.1 Drive units.............................................................................................................10

5.2 Loudspeaker systems............................................................................................10

6 Climatic conditions .........................................................................................................10

7 Acoustical environment ..................................................................................................10

8 Preconditioning ..............................................................................................................10

9 Time-varying properties of the loudspeaker ....................................................................11

10 Methods of measurement ...............................................................................................11

10.1 General .................................................................................................................11

10.2 Static or quasi-static method .................................................................................11

10.3 Point-by-point dynamic method .............................................................................12

10.4 Full dynamic method .............................................................................................14

11 Nonlinear force factor .....................................................................................................15

11.1 Force factor curve Bl(x) .........................................................................................15

11.2 Force-factor limited displacement, X ...................................................................16

11.3 Symmetry point, x (x )......................................................................................17

sym ac

11.4 Voice coil offset, x ..........................................................................................18

offset

12 Nonlinear stiffness..........................................................................................................18

12.1 Nonlinear stiffness curve K (x) ............................................................................18

12.2 Compliance-limited displacement x ......................................................................19

12.3 Stiffness asymmetry A (x )..............................................................................19

peak

13 Displacement-dependent inductance, L (x).....................................................................20

13.1 Inductance curve L (x) ..........................................................................................20

13.2 Inductance-limited displacement, x ......................................................................21

14 Current -dependent inductance, L (i)..............................................................................21

14.1 Characteristic to be specified ................................................................................21

14.2 Method of measurement ........................................................................................21

15 Parameters derived from geometry and performance......................................................22

15.1 Maximal peak displacement, x .......................................................................22

MAXd

15.2 Method of measurement ........................................................................................22

Bibliography..........................................................................................................................23

Figure 1 – Electro-dynamical transducer .................................................................................7

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SIST EN 62458:2011
62458 © IEC:2010(E) – 3 –

Figure 2 –Static and quasi-static measurement setup ...........................................................12

Figure 3 – Setup for measurement of large signal parameters by using the point-by-

point dynamic method...........................................................................................................13

Figure 4 – Setup for dynamic measurement of large signal parameters.................................14

Figure 5 – Reading the maximal peak displacement x limited by force factor only ...............16

Figure 6 – Reading the voice coil offset from the symmetry point x (x ) curve..................17

sym ac
Figure 7 – Definition of the symmetry point x in the nonlinear force factor
sym

characteristic Bl(x) ................................................................................................................18

Figure 8 – Reading the stiffness asymmetry from the K (x) curve .......................................20

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SIST EN 62458:2011
– 4 – 62458 © IEC:2010(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SOUND SYSTEM EQUIPMENT –
ELECTROACOUSTICAL TRANSDUCERS –
MEASUREMENT OF LARGE SIGNAL PARAMETERS
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

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.

International Standard IEC 62458 has been prepared by IEC technical committee 100: Audio,

video and multimedia systems and equipment.

This first edition cancels and replaces IEC/PAS 62458 published in 2006. It constitutes a

technical revision. The main changes are listed below:

– descriptions of the methods of measurement are adjusted to the state of the technology;

– addition of Clauses 4 to 15;
– integration of Annex A in the main body of the standard;
– overall textual review.
---------------------- Page: 10 ----------------------
SIST EN 62458:2011
62458 © IEC:2010(E) – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
100/1624/FDIS 100/1647/RVD

Full information on the voting for the approval of this standard 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.

The committee has decided that the contents of this publication will remain unchanged until

the maintenance result 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

• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The “colour inside” logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this publication using a colour printer.

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SIST EN 62458:2011
– 6 – 62458 © IEC:2010(E)
INTRODUCTION

Electro-mechanical-acoustical transducers such as loudspeaker drive units, loudspeaker

systems, headphones, micro-speakers, shakers, and other actuators behave in a nonlinear

manner at higher amplitudes. This limits the acoustical output and generates nonlinear signal

distortion. Linear models fail in describing the large signal behaviour of such transducers and

extended models have been developed which consider dominant nonlinearities in the motor

and suspension. The free parameters of the large signal model have to be measured on the

particular transducer by using static or dynamic methods. The large signal parameters show

the physical cause of the signal distortion directly and are very important for the objective

assessment of sound quality and failure diagnostics in development and manufacturing.

Furthermore, the model and parameters identified for a particular transducer are the basis for

predicting the maximum output and signal distortion for any input signal. The close

relationship between causes and symptoms simplifies the interpretation of the harmonic and

intermodulation distortion measured according to IEC 60268-5. Large signal parameters are

valuable input data for the synthesis of loudspeaker systems and the development of

electrical control systems dedicated to loudspeakers.
---------------------- Page: 12 ----------------------
SIST EN 62458:2011
62458 © IEC:2010(E) – 7 –
SOUND SYSTEM EQUIPMENT –
ELECTROACOUSTICAL TRANSDUCERS –
MEASUREMENT OF LARGE SIGNAL PARAMETERS
1 Scope

This International Standard applies to transducers such as loudspeaker drive units,

loudspeaker systems, headphones, micro-speakers, shakers and other actuators using either

an electro-dynamical or electro-magnetic motor coupled with a mechanical suspension. The

large signal behaviour of the transducer is modelled by a lumped parameter model

considering dominant nonlinearities such as force factor, stiffness and inductance as shown in

Figure 1. The standard defines the basic terms and parameters of the model, the methods of

measurements and the way the results should be reported.
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 60268-1, Sound system equipment – Part 1: General
IEC 60268-5:2003, Sound system equipment – Part 5: Loudspeakers
Amendment 1 (2007)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
electro-mechanical equivalent circuit
electrical circuit of an electro-dynamical transducer, as shown in Figure 1
L (x, i )
2 3
R (T ) L (x, i)
F C (x) M R
e V e m ms
ms ms
R (x, i )
2 2
load
u Bl(x) v Bl(x) Bl(x) i
IEC 2511/09

NOTE 1 This Figure shows an example of a lumped parameter model of an electro-dynamical transducer

considering the dominant nonlinearities.

NOTE 2 Other equivalent circuits can be applied. Contrary to the results of linear modelling some parameters of

the lumped elements are not constant but depend on instantaneous state variables (such as displacement x,

velocity v, current i).
Figure 1 – Electro-dynamical transducer
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SIST EN 62458:2011
– 8 – 62458 © IEC:2010(E)
3.2
input current and voltage
i, u
electrical state variables at the terminals of the transducer
3.3 displacement
deflection of the voice coil from the rest position
3.4
velocity
time derivative of displacement x
3.5
d.c. resistance

electrical impedance Z (s) at very low frequencies where the effect of the back EMF can be

neglected

NOTE Electrical impedance can be used for measuring the d.c. resistance R of the voice coil. The d.c. resistance

R depends on the mean voice coil temperature T
e V.
3.6
nonlinear inductance and losses

nonlinear elements to model the effect of the magnetic a.c. field, the losses in the magnetic

material, and the losses caused by eddy currents where the equivalent circuit in Figure 1 uses

the LR-2 model comprising the inductance L (x, i), the inductance L (x, i ) and additional

e 2 2
resistance R (x, i )
2 3
3.7
nonlinear force factor
Bl(x)

dependency of instantaneous force factor Bl(x) on voice coil displacement x defined by the

integral of magnetic flux density B versus the voice-coil conductor of length l

NOTE The product of force factor Bl(x) and velocity v is the back EMF generated on the electrical side in an

equivalent circuit as shown in Figure 1. The product of force factor Bl(x) and input current i gives the electro-

dynamical driving force of the mechanical system.
3.8
reluctance force

additional electro-magnetic driving force caused by the displacement varying inductances

(x, i) and L (x, i )
e 2 2
3.9
stiffness, K (x), of the suspension

ratio between the instantaneous restoring force F(x) and the displacement x as given by

F()x
K x = (1)

NOTE The nonlinear compliance C (x) = 1/K (x) is the reciprocal quantity of the mechanical stiffness.

ms ms
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SIST EN 62458:2011
62458 © IEC:2010(E) – 9 –
3.10
mechanical mass

total moving mass including the mass of the moving assembly and the reactive part of the air

load on both sides of the diaphragm
3.11
mechanical resistance

non-electrical losses of the driver, due to suspension, turbulences and radiation

3.12
mechanical impedance
load

mechanical impedance which may represent any additional load caused by mechanical

elements (cone, panel) or acoustical elements (such as a vented enclosure or horn)

4 Test signals
4.1 General

The measurement of the large signal parameters requires an electrical, mechanical or

acoustical stimulus. Depending on the method used for the measurement of the large signal

parameters different kind of test signals are used as stimulus for the excitation of the

transducer. Since the loudspeaker behaves as a time-varying system the stimulus may cause

a permanent or temporary change of the loudspeaker properties. Thus, the properties of the

stimulus (spectral bandwidth, crest factor, proability density function) shall be statet. The

same stimulus should be used if the numerical values of the results should be compared from

two measurements.
4.2 Large d.c. signal

A constant d.c. voltage or d.c current of defined magnitude and sufficient duration is supplied

to the electrical terminals to measure the steady-state response of the transducer. If the

transducer is mounted in a sealed enclosure a difference between the static air pressures

inside and outside the enclosure may be used as d.c. stimulus.
4.3 Large d.c. signal and small a.c. signal

A constant d.c. signal of defined magnitude and sufficient duration (see 4.2) superimposed

with a small a.c. signal is used as stimulus. The a.c. signal (such as noise, sinusoidal sweep,

impulsive test signals) should have sufficient bandwidth to identify all parameters of the

loudspeaker model.
4.4 Broadband noise signal

One of the noise signals defined in IEC 60268-1 or any other noise having sufficient

bandwidth and amplitude may be used as stimulus. The crest factor of the noise should be

less than 4 to reduce clipping in the amplifier.
4.5 Music

Ordinary music, speech of sufficient bandwidth and amplitude may be used as a stimulus.

NOTE The dynamic methods need a stimulus which provides persistent excitation of the loudspeaker to identify

the parameters correctly. The stimulus should have enough spectral components at least one octave below

resonance frequency f and one decade above f .
s s
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SIST EN 62458:2011
– 10 – 62458 © IEC:2010(E)
5 Mounting condition
5.1 Drive units
The driver unit may be mounted
a) in free air without a baffle or enclosure,
b) in a standard baffle according to 11.1 of IEC 60268-5,
c) in half-space free field according to 5.2 of IEC 60268-5,
d) in the standard measuring enclosure (type A or type B) according to 11.2 of
IEC 60268-5, or another, specified enclosure,
e) in vacuum,
f) other configuration defined in the presentation of the results.

The acoustic loading depends upon the mounting arrangement, which shall be clearly

described in the presentation of the results.

During the measurement the transducer should be firmly clamped to suppress additional

mechanical resonances close to the resonance frequency f . A vertical position of the

transducer (cone displacement in horizontal direction) is recommended to avoid any bias due

the weight of the moving assembly.

Drive units for horn loaded loudspeakers, headphones, micro-speakers and microphones

should preferably be measured in a vacuum to reduce the acoustic load, suppress additional

acoustic resonances, and to avoid nonlinear damping due to turbulent air flow.
5.2 Loudspeaker systems

Loudspeaker systems are measured under conditions which correspond with the intended use.

6 Climatic conditions

The measurements should be made at an ambient temperature 15°C to 35°C, preferably at

20°C, relative humidity 25 % to 75 %, air pressure 86 kPa to 106 kPa as specified in

IEC 60268-1 to avoid any influence of temperature and humidity that may affect the properties

of the drive unit suspensions.
7 Acoustical environment

The measurement room shall be large enough that the influence of the acoustical environment

on the mechanical vibration of the transducer is negligible.

If the measurement of the large signal parameters is based on sound pressure output it is

recommended to place the measuring microphone in the near field of the transducer. It is

recommended to use a method that measures electrical or mechanical signals only, which is

thus immune to unwanted acoustic noise.
8 Preconditioning

The loudspeaker should be preconditioned according to Clause 12 of IEC 60268-5. A

temporary voice coil offset caused by storing the transducer for some time in the horizontal

position can be removed by operating the transducer for at least 5 min in the vertical position

before performing the regular measurement.
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SIST EN 62458:2011
62458 © IEC:2010(E) – 11 –
9 Time-varying properties of the loudspeaker

The stimulus provided to the electrical input of the loudspeaker may cause a heating of the

voice coil and may also change the properties of the suspension during measurement. Thus,

the electrical resistance of the coil should be measured during measurement and considered

in the calculation of the loudspeaker parameters (e.g. electrical loss factor Q ).

10 Methods of measurement
10.1 General

The following methods may be used for the measurement of the large signal parameters. The

method used should be stated together with the results.
10.2 Static or quasi-static method
10.2.1 General

This technique determines the non-linear parameters of the transducer by using a d.c. signal

with magnitude u (usually voltage) as stimulus. After reaching steady state relevant state

variables (d.c. displacement x , d.c. force F ) are measured and the parameter value (such as

i i

K(x ) = F /x ) is calculated. After changing the magnitude of the d.c. signal the measurement is

i i i

repeated at further working points x with i = 1, …, N to measure the non-linear parameters

within the working range –x < x < x with sufficient resolution.
peak i peak

Due to the visco-elastic behaviour of the suspension material, the settling time required to

reach steady state may exceed several seconds and a static method is very time consuming.

In a quasi-static method the state variables are measured before steady state is reached and

the settling time used should be stated.

Creep and other visco-elastic properties of the suspension cause significant discrepancies

between the stiffness K(x) measured statically by using a d.c. signal and the stiffness K (x)

measured dynamically by using an broadband noise signal.

The d.c. signal of the static and quasi-static methods cannot be used for the measurement of

L (x, i). Figure 2 shows a setup for static and quasi-static
the nonlinear voice coil inductance
measurement of large signal parameters.
---------------------- Page: 17 ----------------------
SIST EN 62458:2011
– 12 – 62458 © IEC:2010(E)
Transducer Sensor
DC signal
generator
Parameter Measured
calculation signal
Input
signal
Parameter value
at working point u
Selection of working
point
Large signal
parameters
IEC 2512/09
Figure 2 –Static and quasi-static measurement setup
10.2.2 Procedure
Procee
...

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