ISO 7240-24:2010

Fire detection and fire alarm systems - Part 24: Sound-system loudspeakers

ISO 7240-24:2010 specifies requirements, test methods and performance criteria for loudspeakers intended to broadcast a warning of fire between a fire detection and alarm system and the occupants of a building (see item C4 of ISO 7240-1:2005). ISO 7240-24:2010 specifies loudspeakers for two types of application environment: type A, generally for indoor use, and type B, generally for outdoor use. ISO 7240-24:2010 does not cover loudspeakers for special applications, for example loudspeakers for use in hazardous applications, if such applications require additional or other requirements or tests other than those given in ISO 7240-24:2010. ISO 7240-24:2010 is not intended to cover addressable loudspeakers or loudspeakers with active components. Aural alarm indicators are covered in the future ISO 7240-3.

Systèmes de détection d'incendie et d'alarme — Partie 24: Haut-parleurs pour systèmes d'alarme vocale

General Information

• Status: Withdrawn
• Publication Date: 23-Feb-2010
• Withdrawal Date: 23-Feb-2010
• ICS: 13.220.20 - Fire protection
• Technical Committee: ISO/TC 21/SC 3 - Fire detection and alarm systems
• Drafting Committee: ISO/TC 21/SC 3 - Fire detection and alarm systems
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 08-Apr-2016
• Completion Date: 13-Dec-2025

Relations

• Amended By: ISO 7240-24:2010/Amd 1:2013 - Fire detection and fire alarm systems - Part 24: Sound-system loudspeakers - Amendment 1
• Effective Date: 09-May-2020
• Revised: ISO 7240-24:2016 - Fire detection and fire alarm systems - Part 24: Fire alarm loudspeakers
• Effective Date: 05-Nov-2015

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 7240-24
First edition
2010-03-01
Fire detection and fire alarm systems —
Part 24:
Sound-system loudspeakers
Systèmes de détection d'incendie et d'alarme —
Partie 24: Haut-parleurs pour systèmes d'alarme vocale

Reference number
©
ISO 2010
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©  ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .iv
Introduction.vi
1 Scope.1
2 Normative references.1
3 Terms, abbreviated terms and definitions.2
3.1 Terms and definitions .2
3.2 Abbreviated terms .5
4 Requirements.5
4.1 Compliance .5
4.2 Frequency response limits.5
4.3 Durability .6
4.4 Construction .6
4.5 Marking and data .6
5 Tests .8
5.1 General .8
5.2 Reproducibility .11
5.3 Rated impedance.12
5.4 Horizontal and vertical coverage angles.13
5.5 Maximum sound pressure level.14
5.6 Rated noise power (durability).14
5.7 Dry heat (operational) .15
5.8 Dry heat (endurance).16
5.9 Cold (operational).17
5.10 Damp heat, cyclic (operational) .17
5.11 Damp heat, steady state (endurance).18
5.12 Damp heat, cyclic (endurance) .19
5.13 Sulfur dioxide (SO ) corrosion (endurance).20
5.14 Shock (operational) .21
5.15 Impact (operational) .22
5.16 Vibration, sinusoidal (operational) .23
5.17 Vibration, sinusoidal (endurance) .24
5.18 Ingress protection .25
6 Test report.26
Annex A (normative) Acoustical measurements.27
Annex B (normative) Measuring rated noise power (durability).31
Annex C (informative) Loudspeaker physical references.37
Bibliography.39

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 7240-24 was prepared by Technical Committee ISO/TC 21, Equipment for fire protection and fire fighting,
Subcommittee SC 3, Fire detection and alarm systems.
ISO 7240 consists of the following parts, under the general title Fire detection and fire alarm systems:
⎯ Part 1: General and definitions
⎯ Part 2: Control and indicating equipment
⎯ Part 3: Audible alarm indicators
⎯ Part 4: Power supply equipment
⎯ Part 5: Point-type heat detectors
⎯ Part 6: Carbon monoxide fire detectors using electro-chemical cells
⎯ Part 7: Point-type smoke detectors using scattered light, transmitted light or ionization
⎯ Part 8: Carbon monoxide fire detectors using an electro-chemical cell in combination with a heat sensor
⎯ Part 9: Test fires for fire detectors [Technical Specification]
⎯ Part 10: Point-type flame detectors
⎯ Part 11: Manual call points
⎯ Part 12: Line type smoke detectors using a transmitted optical beam
⎯ Part 13: Compatibility assessment of system components
⎯ Part 14: Guidelines for drafting codes of practice for design, installation and use of fire detection and fire
alarm systems in and around buildings [Technical report]
iv © ISO 2010 – All rights reserved

⎯ Part 15: Point type fire detectors using scattered light, transmitted light or ionization sensors in
combination with a heat sensor
⎯ Part 16: Sound system control and indicating equipment
⎯ Part 17: Short-circuit isolators
⎯ Part 18: Input/output devices
⎯ Part 19: Design, installation, commissioning and service of sound systems for emergency purposes
⎯ Part 20: Aspirating smoke detectors
⎯ Part 21: Routing equipment
⎯ Part 22: Smoke-detection equipment for ducts
⎯ Part 24: Sound-system loudspeakers
⎯ Part 25: Components using radio transmission paths
⎯ Part 27: Point-type fire detectors using a scattered-light, transmitted-light or ionization smoke sensor, an
electrochemical-cell carbon-monoxide sensor and a heat sensor
⎯ Part 28: Fire protection control equipment
A Part 23, dealing with visual alarm indicators, is under development.
Introduction
This part of ISO 7240 is based on European standard EN 54-24, prepared by the European Committee for
Standardization's Technical Committee CEN/TC 72, Fire detection and fire alarm systems.
The purpose of a sound-system loudspeaker as a component of a sound system for emergency purposes
(see ISO 7240-19) is to provide intelligible warning to people in or within the vicinity of a building in which a
fire emergency has occurred and to enable such person(s) to take appropriate measures in accordance with a
predetermined evacuation plan.
The primary reason for using a sound system for emergency purposes, instead of coded warnings given by
aural alarm indicators (see the future ISO 7240-3) is to reduce the time taken for those at risk to recognize
that an emergency exists, and to give clear instructions on what to do next. This means that sound-system
loudspeakers are required to achieve a minimum acoustical performance, as well as constructional and
environmental requirements, to be suitable for use in a sound system for emergency purposes.
This part of ISO 7240 recognizes that the exact nature of the acoustical requirements for sound-system
loudspeakers varies according to the nature of the space into which they are installed. It therefore specifies
the minimum requirements that apply to sound-system loudspeakers and a common method for testing their
operational performance against parameters specified by the manufacturers.
This part of ISO 7240 gives common requirements for the construction and robustness of sound-system
loudspeakers as well as their performance under climatic and mechanical conditions that are likely to occur in
the service environment. As the types of loudspeaker considered in this part of ISO 7240 are passive
electromechanical devices not involving sensitive electronic circuits, electromagnetic compatibility (EMC) tests
have not been included. The loudspeakers have been classified for either an indoor or an outdoor application
environment category.
This part of ISO 7240 requires that manufacturers specify certain characteristics in a consistent manner so
that designers can make objective decisions about which loudspeaker to use in specific applications.

vi © ISO 2010 – All rights reserved

INTERNATIONAL STANDARD ISO 7240-24:2010(E)

Fire detection and fire alarm systems —
Part 24:
Sound-system loudspeakers
1 Scope
This part of ISO 7240 specifies requirements, test methods and performance criteria for loudspeakers
intended to broadcast a warning of fire between a fire detection and alarm system and the occupants of a
building (see item C of ISO 7240-1:2005).

This part of ISO 7240 specifies loudspeakers for two types of application environment: type A, generally for
indoor use, and type B, generally for outdoor use.
This part of ISO 7240 does not cover loudspeakers for special applications, for example loudspeakers for use
in hazardous applications, if such applications require additional or other requirements or tests other than
those given in this part of ISO 7240.
This part of ISO 7240 is not intended to cover addressable loudspeakers or loudspeakers with active
components.
Audible alarm indicators are covered in the future ISO 7240-3.
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.
ISO 7240-1, Fire detection and alarm systems — Part 1: General and definitions
ISO 9001:2008, Quality management systems — Requirements
IEC 60068-1, Environmental testing — Part 1: General and guidance
IEC 60068-2-1, Environmental testing — Part 2-1: Tests — Test A: Cold
IEC 60068-2-2, Environmental testing — Part 2-2: Tests — Test B: Dry heat
IEC 60068-2-6, Environmental testing — Part 2-6: Tests — Test Fc: Vibration (sinusoidal)
IEC 60068-2-27, Environmental testing — Part 2-27: Tests — Test Ea and guidance: Shock
IEC 60068-2-30, Environmental testing — Part 2-30: Tests — Test Db: Damp heat, cyclic (12 h + 12 h cycle)
IEC 60068-2-42, Environmental testing — Part 2-42: Tests — Test Kc: Sulphur dioxide test for contacts and
connections
IEC 60068-2-75:1997, Environmental testing — Part 2-75: Tests — Test Eh: Hammer tests
IEC 60068-2-78, Environmental testing — Part 2-78: Tests — Test Cab: Damp heat, steady state
IEC 60268-1:1985, Sound system equipment — Part 1: General
IEC 60529, Degrees of protection provided by enclosures (IP code)
IEC 60695-11-10, Fire hazard testing — Part 11-10: Test flames — 50 W horizontal and vertical flame test
methods
IEC 60695-11-20, Fire hazard testing — Part 11-20: Test flames — 500 W flame test methods
IEC 61260, Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications
EN 50130-4, Alarm systems — Part 4: Electromagnetic compatibility — Product family standard: Immunity
requirements for components of fire, intruder and social alarm systems
3 Terms, abbreviated terms and definitions
For the purposes of this document, the terms, definitions and symbols given in ISO 7240-1 and the following
apply.
3.1 Terms and definitions
3.1.1
1/3 octave
frequency band as defined in IEC 61260
3.1.2
coverage angle
smallest angle between two directions on either side of the reference axis at which the sound pressure level is
6 dB less than the sound pressure level on the reference axis
NOTE This angle is measured in the vertical and horizontal planes.
3.1.3
free-field condition
acoustical environment in which the sound pressure decreases with the distance, r, from a point source
according to a 1/r law, with an accuracy of ± 10 %, in the region that is occupied by the sound field between
the loudspeaker system and the microphone during the measurements
EXAMPLE An anechoic room, a quiet outdoor space.
3.1.4
frequency response
sound pressure level at a distance of 4 m from the reference point on the reference axis, produced at
1/3 octave frequency bands, from 100 Hz to 10 kHz (centre frequencies)
NOTE This is also referred to as magnitude or amplitude response.
2 © ISO 2010 – All rights reserved

3.1.5
ground plane measurement
measurement under half-space free-field conditions used to simulate a free-field condition in which the
loudspeaker is mounted above an acoustically totally reflective boundary surface and aimed so that its
reference axis points towards a measurement microphone that is placed directly on the boundary surface
NOTE In order to achieve measurement results that are comparable with a free-field condition, ground-plane
measurements need to be corrected by −6 dB at all frequencies.
3.1.6
half-space free-field condition
acoustical environment that is confined by a plane of sufficient size and in which the free-field exists in a
hemisphere, so that the sound pressure from a point source mounted in the surface of that plane decreases in
the manner defined in the free-field condition
EXAMPLE A half-space anechoic room.
3.1.7
horizontal plane
virtual plane of the loudspeaker containing the reference axis, as specified by the manufacturer
NOTE There may be several horizontal planes corresponding to several reference axes.
EXAMPLE See Annex C.
3.1.8
loudspeaker
transducer that converts electrical energy into acoustical energy, comprised of one or more drive units, one or
more enclosures, a cable termination block and relevant devices such as filters, transformers and any passive
element
NOTE Some loudspeakers are a combination of one or more loudspeaker housing(s) and a termination box
interconnected by a cable. The loudspeaker housing(s), cable(s) and terminal box should be considered to be “the
loudspeaker” for the purposes of this part of ISO 7240. Examples of such loudspeakers include pendant types and
loudspeakers with mechanically adjustable orientation such as horn or column loudspeakers and loudspeaker arrays.
3.1.9
loudspeaker enclosure
any parts of the outer physical envelope of the loudspeaker that prevents or restricts access of solid foreign
objects to the sound transducer, internal components and cable termination block
3.1.10
maximum sound pressure level
total sound pressure level at 4 m from the reference point on the reference axis of a loudspeaker supplied with
a simulated program signal at the rated noise power
3.1.11
measuring distance
distance between the reference point and the measuring microphone
3.1.12
pink noise
random noise signal with a spectral density that decreases by 3 dB per octave, giving constant energy per
octave
3.1.13
rated impedance
value of pure resistance, stated by the manufacturer, that is substituted for the loudspeaker when defining the
required power of the source
3.1.14
rated noise power
electrical power calculated from the formula UR/ , where U is the rated noise voltage and R is the rated
n
n
impedance
NOTE 1 For transformer-coupled loudspeakers, the rated noise power is the highest power setting specified by the
manufacturer.
NOTE 2 The rated noise power is also called power-handling capacity.
3.1.15
rated noise voltage
RMS voltage, as specified by the manufacturer, of the simulated program signal that the loudspeaker can
sustain without thermal or mechanical damage
NOTE 1 See Annex B.
NOTE 2 For transformer-coupled loudspeakers, the rated noise voltage typically equals 50 V, 70 V or 100 V.
3.1.16
reference axis
virtual axis of the loudspeaker as specified by the manufacturer
NOTE There may be several reference axes.
EXAMPLE See Annex C.
3.1.17
reference plane
virtual plane perpendicular to the reference axis as specified by the manufacturer
EXAMPLE See Annex C.
3.1.18
reference point
point at the intersection of the reference plane and the reference axis
EXAMPLE See Annex C.
3.1.19
sensitivity
sound pressure level, S, of a loudspeaker supplied with a 1 W pink noise signal from 100 Hz to 10 kHz
measured at a distance of 4 m from the reference point on the reference axis
3.1.20
simulated program signal
signal whose mean power spectral density closely resembles the average of the mean power spectral
densities of a wide range of audio signals
EXAMPLE See Annex B.
3.1.21
type A loudspeaker
loudspeaker that is primarily intended for indoor applications
NOTE Type A loudspeakers may be suitable for some protected outdoor situations.
3.1.22
type B loudspeaker
loudspeaker that is primarily intended for outdoor applications
4 © ISO 2010 – All rights reserved

NOTE Type B loudspeakers may be more suitable than type A for some indoor situations where high temperature or
humidity is present.
3.1.23
vertical plane
virtual plane of the loudspeaker perpendicular to the horizontal plane and containing the reference axis
EXAMPLE See Annex C.
3.2 Abbreviated terms
⎯ DC direct current
⎯ RMS root mean square
4 Requirements
4.1 Compliance
In order to conform to this part of ISO 7240, loudspeakers shall meet the requirements of Clause 4, which shall
be verified by visual inspection or engineering assessment, shall be tested as described in Clause 5 and shall
meet the requirements of the tests.
4.2 Frequency response limits
The loudspeaker frequency response shall fit within the unshaded area shown in Figure 1.
NOTE If the frequency response shown in Figure 1 can be achieved only by means of a frequency equalizer that is
specified by the manufacturer for normal use [see 4.5.2 h)], it is acceptable to insert a dedicated equalizer in the
measurement setup (see 5.1.6).

Key
X 1/3 octave band centre frequency, expressed in hertz
Y relative level, expressed in decibels
Figure 1 — Frequency response limit
4.3 Durability
The loudspeaker shall be rated for at least 100 h operation at the rated noise power specified by the
manufacturer (refer to the test procedure described in 5.6).
4.4 Construction
4.4.1 Provision for external conductors
The loudspeaker shall provide space within its enclosure for entry and termination of external conductors.
Entry holes for conductors or cables shall be provided or the location where such holes can be made shall be
indicated by providing a template or some other suitable means.
Terminals for connecting external conductors shall be designed so that they are clamped between metal
surfaces without being damaged.
4.4.2 Materials
The loudspeaker shall be constructed of material(s) capable of withstanding the tests specified in Clause 5. In
addition, the material(s) of plastic enclosures shall conform to the following flammability requirements:
a) IEC 60695-11-10 Class V-2 or HB75 for devices operating from a voltage source less than or equal to
30 V RMS or 42,4 V DC and dissipating less than 15 W;
b) IEC 60695-11-20 Class 5VB for devices operating from a voltage source greater than 30 V RMS or
42,4 V DC and dissipating more than 15 W.
4.4.3 Ingress protection
The degree of protection provided by the enclosure of loudspeakers shall conform to the following
requirements:
⎯ for type A, indoor applications: Code IP21C of IEC 60529;
⎯ for type B, outdoor applications: Code IP33C of IEC 60529.
4.4.4 Access
Means shall be provided to limit access for removal of parts of or the whole device and to make adjustment to
the mode of operation, e.g. special tool, codes, hidden screws, seals.
4.5 Marking and data
4.5.1 Marking
Each loudspeaker shall be clearly marked with the following information:
a) number of this part of ISO 7240 (i.e. ISO 7240-24);
b) classification (i.e. type A or type B);
c) name or trademark of the manufacturer or supplier;
d) manufacturer or supplier model designation (type or number);
e) wiring terminal designations;
6 © ISO 2010 – All rights reserved

f) for transformer-coupled loudspeakers, rated noise voltage;
g) for direct-coupled loudspeakers, rated impedance;
h) rated noise power (at the highest power setting);
i) power settings (e.g. transformer tapping options for transformer-coupled loudspeakers);
j) mark(s) or code(s) (e.g. a serial number or batch code), by which the manufacturer can identify at least
the date or batch and place of manufacture.
Where any marking on the device uses symbols or abbreviations not in common use, these shall be explained
in the data supplied with the device.
It is not necessary that the marking be discernible when the device is installed and ready for use but shall be
visible during installation and shall be accessible during maintenance.
The markings shall not be placed on screws or other easily removable parts.
4.5.2 Data
The information required in 4.5.1 together with the following shall be supplied with the device, or shall be given
in a data sheet or technical manual identified on, or with, each device:
a) frequency response for each stated reference axis;
b) sensitivity for the stated reference axis (see 5.1.5);
c) horizontal and vertical coverage angles at 500 Hz, 1 kHz, 2 kHz, 4 kHz for each stated reference plane,
measured as described in 5.4.2;
d) maximum sound pressure level (at highest power setting) for each stated reference plane, measured as
described in 5.5.2;
e) reference axis, reference plane and horizontal plane;
f) rated noise power, measured as described in 5.6.2;
g) rated impedance for each tapping, measured as described in 5.3.2;
h) 1/3 octave band frequency response of any dedicated active equalization that can be required;
i) any other information necessary to enable correct installation, operation and maintenance of the device;
j) acoustical measurement environment used for the specifications listed in this data sheet, e.g. free-field,
half-space free-field, standard baffle.
If different settings, except power settings, are available on the loudspeaker, such as tone control or
adjustable parts, the manufacturer shall specify the applicable configuration(s) for each setting.
5 Tests
5.1 General
5.1.1 Atmospheric conditions for tests
Unless otherwise stated in a test procedure, carry out the testing after the test specimen has been allowed to
stabilize in the standard atmospheric conditions for testing described in IEC 60068-1 as follows:
⎯ temperature: (15 to 35) °C;
⎯ relative humidity: (25 to 75) %;
⎯ air pressure: (86 to 106) kPa.
The temperature and humidity shall be substantially constant for each environmental test where the standard
atmospheric conditions are applied.
5.1.2 Operating conditions for tests
Unless otherwise stated in a test procedure the test specimen shall be
a) set to its highest power setting;
b) preconditioned in accordance with Annex A;
c) mounted in the acoustical environment as described in Annex A and as specified by the manufacturer
[see 4.5.2 j)].
If different settings, except power settings, are available on the loudspeaker, such as tone control or adjustable
parts (excluding external mounting bracket), the manufacturer shall specify the configuration(s) to be tested.
The details of the settings shall be given in the test report (see Clause 6).
5.1.3 Mounting arrangements
For environmental conditioning tests, unless otherwise specified, the specimen shall be mounted by its normal
means of attachment in accordance with the manufacturer's instructions. If these instructions describe more
than one method of mounting, the method considered as the most unfavourable shall be chosen for each test.
For some loudspeakers, due to their size, it might not be practical to conduct all of the environmental tests. In
such cases, testing may be carried out on a smaller representative specimen, where this is deemed to
produce a valid result for a given test.
5.1.4 Tolerances
The tolerances for the environmental test parameters shall be given in the basic reference standards for the
test (e.g. the relevant part of IEC 60068).
If a specific tolerance or deviation limit is not specified in a requirement or test procedure, then a deviation
limit of ± 5 % shall be applied.
5.1.5 Frequency response measurement and sensitivity calculation
5.1.5.1 Measuring arrangement
Measurements shall be made in accordance with Annex A.
8 © ISO 2010 – All rights reserved

5.1.5.2 Measurements
Measure the sound pressure level, L , in 1/3 octave bands from 100 Hz to 10 kHz, at the measuring distance
m,i
on the reference axis, when the loudspeaker is supplied with a band-filtered noise signal of constant voltage.
Levels L shall be the average true RMS values over a period of at least
m,i
⎯ 10 s for 1/3 octave bands from 100 Hz to 400 Hz;
⎯ 3 s for 1/3 octave bands from 500 Hz to 1,6 kHz;
⎯ 1 s for 1/3 octave bands from 2 kHz to 10 kHz.
Perform the measurement by supplying the loudspeaker
a) either sequentially with a 1/3 octave band filtered pink noise signal such that the square of the RMS
voltage divided by the rated impedance equals 1 W. In this case the measured sound pressure levels in
each 1/3 octave band (L ) shall be corrected (L ) as given in Equation (1):
m,i c,i
LL=−10×log (21) (1)
ci,,m i 10
b) or with a pink noise signal such that the square of the RMS voltage divided by the rated impedance
equals 1 W spread over the full range of frequencies (from 100 Hz to 10 kHz, 1/3 octave bands) and
analysing the microphone output signal by means of 1/3 octave filters as given in Equation (2):
L = L (2)
ci,,m i
NOTE The method described in a) is better suited for loudspeakers with low power drive unit(s), typically 1 W or less.
The method described in b) is preferred for loudspeakers with higher power drive unit(s).
For loudspeakers with a rated noise power of less than 1 W, a pink noise signal of less than 1 W may be used
providing L is corrected accordingly.
c,i
Plot the frequency response with the sound pressure levels, L , as a function of frequency in 1/3 octave
c,i
bands. Adjust the 0 dB reference of the tolerance field (see Figure 1) to give the best fit with the frequency
response curve.
5.1.5.3 Sensitivity calculation
The sensitivity, S, expressed in decibels, shall be given by Equation (3):
L
⎡⎤ci,
()
⎢⎥
S=×10 log 10 (3)
10∑
⎢⎥
i=1
⎢⎥
⎣⎦
where L to L are the 1/3 octave sound pressure levels from 100 Hz to 10 kHz from the frequency
c,1 c,21
response curve.
5.1.6 Frequency response measurement and sensitivity calculation for loudspeakers requiring
dedicated system equalization
5.1.6.1 General
This test method shall be used for loudspeakers that have been designed to operate with an associated active
equalization network.
NOTE Testing of active equalizers is not covered by this part of ISO 7240.
5.1.6.2 Measuring arrangement
Make the measurements in accordance with Annex A.
An active equalizer inserted between the clipping network and the power amplifier shall be used in the
measurements.
5.1.6.3 Measurements
Perform the measurement described in 5.1.5.2.
5.1.7 Provision for tests
The following shall be provided for testing compliance with this part of ISO 7240:
a) seven specimens of type A or nine specimens of type B loudspeaker with any mounting, accessories etc.;
b) data required in 4.5.2.
The specimens submitted shall be representative of the manufacturer's normal production with regard to their
construction and settings.
5.1.8 Test schedule
The specimens shall be tested and inspected in accordance with the schedule given in Table 1.
All the specimens shall first be submitted to the reproducibility test described in 5.2. On completion of the
reproducibility test, the specimen with the least sensitivity shall be numbered 1 and the rest arbitrarily
numbered from 2 to 7 for type A or 2 to 9 for type B.
Unless otherwise specified in the test procedure, the loudspeaker setting(s) selected for conducting the
reproducibility test shall be used for the other tests.
10 © ISO 2010 – All rights reserved

Table 1 — Schedule of tests
a, b, c, d
Test Subclause
Specimen number
Type A Type B
Rated impedance 5.3 1 1
Horizontal and vertical coverage angles 5.4 1 1
Maximum sound pressure level 5.5 1 1
Rated noise power (durability) 5.6 2 2
Dry heat (operational) 5.7 3 3
Dry heat (endurance) 5.8 — 8
Cold (operational) 5.9 3 3
Damp heat, cyclic (operational) 5.10 3 3
Damp heat, steady state (endurance) 5.11 3 3
Damp heat, cyclic (endurance) 5.12 — 9
SO corrosion (endurance) 5.13 4 4
Shock (operational) 5.14 5 5
Impact (operational) 5.15 6 6
Vibration, sinusoidal (operational) 5.16 7 7
Vibration, sinusoidal (endurance) 5.17 7 7
Enclosure protection 5.18 1, 2 1, 2
a
Where after one of the tests specified in 5.7 to 5.18 the curve obtained differs from the one measured before the test by more than
± 3 dB and differs with the frequency response performance requirement in 4.2, a new specimen shall be used for the next test on the
schedule for that specimen. The frequency response shall be first measured as specified in 5.1.5 or, if applicable, 5.1.6.
b
In the interest of test economy, it is permitted to use the same specimen for more than one environmental test. However, it is
necessary to recognize that this increases the test time and exposes the specimen to a more severe test regime. It should be noted
that, in the event of failure, it might not be possible to identify which test exposure caused the failure.
c
When the same specimen is submitted to more than one environmental test, the frequency response test may be carried out after
each individual test or at the end of the group of test. In any case, the result after environmental test(s) shall always be compared with
the result obtained during the reproducibility test.
d
It is also permitted that a manufacturer submit a separate specimen for each environmental test. In this case, all the specimens
shall be submitted to the reproducibility test (5.2).

5.2 Reproducibility
5.2.1 Object of the test
To show that the acoustical performance of the loudspeaker does not vary unduly from specimen to specimen
and to establish performance data for comparison with the performance data measured during and/or after the
environmental tests specified in this part of ISO 7240.
5.2.2 Test procedure
Measure and plot the frequency response of all the specimens as described in 5.1.5 or, if applicable, 5.1.6.
Calculate the sensitivity, S, as described in 5.1.5 or, if applicable, 5.1.6 for each specimen.
5.2.3 Requirements
The frequency response curve fits within the limits shown in 4.2;
The sound pressure levels in the 1/3 octave bands with centre frequencies from 500 Hz to 4 kHz are within
± 4 dB of the manufacturer's specified curve.
The sensitivity S is not less than the value specified by the manufacturer.
5.3 Rated impedance
5.3.1 Object of the test
To check that the rated impedance specified by the manufacturer is achieved.
5.3.2 Test procedure
Supply the loudspeaker with a constant sinusoidal voltage or current swept over the range from 89 Hz to
11,2 kHz.
Select a voltage or current level such that the loudspeaker operates within its linear region.
Measurements of impedance can be strongly influenced by the drive level. If the level is either too low or too
high, inaccurate results can be obtained. These data should be examined for consistency at several drive
levels in order to establish the best conditions.
Measure the following within the full frequency range:
⎯ for the constant voltage method, the RMS current, I; or
⎯ for the constant current method, the RMS voltage, U.
Calculate the lowest impedance modulus, Z , given by the ratio of the RMS voltage to the RMS current, over
min
the full frequency range for each tap setting as follows:
a) for the constant voltage method, as given in Equation (4):
U
Z = (4)
1,min
I
max
where
U is the applied constant voltage;
I is the measured maximum current;
max
b) for the constant current method, as given in Equation (5):
U
min
Z = (5)
2,min
I
where
I is the applied constant current;
U is the measured minimum voltage.
min
12 © ISO 2010 – All rights reserved

5.3.3 Requirements
Neither Z or Z shall be less than 80 % of the rated impedance specified by the manufacturer for
1,min 12,min
each tap setting.
5.4 Horizontal and vertical coverage angles
5.4.1 Object of the test
To check that the horizontal and vertical coverage angles specified by the manufacturer [see 4.5.2 c)] are
achieved.
5.4.2 Test procedure
5.4.2.1 General
Measure the horizontal and vertical coverage angles as described in Annex A.
Use octave band filters centred on 500 Hz, 1 kHz, 2 kHz and 4 kHz.
Perform the measurements by supplying the loudspeaker either
a) with a pink noise signal spread over the full range of frequencies from 89 Hz to 11,2 kHz and analysing
the microphone output signal by means of octave band filters centred on 500 Hz, 1 kHz, 2 kHz and 4 kHz;
or
b) sequentially with an octave band filtered pink noise signal with centre frequencies of 500 Hz, 1 kHz, 2 kHz
and 4 kHz.
The measurement level should be chosen such that the loudspeaker operates within its linear region.
5.4.2.2 Horizontal coverage angle
Measure the sound pressure level for each octave band at the measuring distance in accordance with
Annex A. The measurement value shall be the average RMS value over a period of at least:
⎯ 10 s for the 500 Hz octave band, and
⎯ 3 s for the other octave bands.
Rotate the measuring microphone or the loudspeaker in the horizontal plane in an arc about the reference
point to one side until the sound pressure level is −6 dB from that recorded on the reference axis. Then rotate
the microphone or the loudspeaker to the opposite side of the reference point until the sound pressure level is
−6 dB.
Record the total angular movement in degrees as the horizontal coverage angle for each octave band.
5.4.2.3 Vertical coverage angle
Repeat the procedure as specified in 5.4.2.2 for the vertical plane. Record the total angular movement,
expressed in degrees, as the vertical coverage angle for each octave band.
5.4.3 Requirements
The measured horizontal and vertical coverage angles shall be within ± 5° of the values specified by the
manufacturer.
5.5 Maximum sound pressure level
5.5.1 Object of the test
To check that the maximum sound pressure level specified by the manufacturer is achieved.
5.5.2 Test procedure
5.5.2.1 General
Measure the maximum sound pressure level as described in Annex A.
The clipped noise at the terminals of the loudspeaker under test shall have a peak-to-RMS ratio of between 1,8
and 2,2.
NOTE Peak-to-RMS ratio is commonly called crest factor.
The power amplifier shall have an output impedance not greater than 1/3 of the rated impedance of the
loudspeaker system in accordance with 5.3. The amplifier shall be capable of supplying the loudspeaker with a
peak voltage of a sinusoidal signal that is at least 2,2 times the rated noise voltage of the loudspeaker.
Supply the loudspeaker with the simulated program signal at the rated noise power and over the full range of
frequencies (from 100 Hz to 10 kHz 1/3 octave bands).
5.5.2.2 Measurement of maximum sound pressure level
Measure the maximum sound pressure level, L , expressed in decibels, by integration over a period of at
max
least 30 s, at the measuring distance, on the reference axis.
5.5.3 Requirements
L is not less than the value specified by the manufacturer.
max
5.6 Rated noise power (durability)
5.6.1 Object of the test
To check that the rated noise power specified by the manufacturer is achieved.
5.6.2 Test procedure
5.6.2.1 General
Measure the rated noise power as described in Annex B.
5.6.2.2 Conditioning
Place the loudspeaker in the test room, maintaining standard atmospheric conditions. Operate the speaker at
the rated noise voltage specified by the manufacturer for a continuous period of 100 h.
After the test, maintain the loudspeaker in standard atmospheric conditions for 24 h.
5.6.2.3 Measurements during conditioning
For loudspeakers that incorporate protective devices, continuously monitor the RMS current consumption,
with an integration time between 3 s and 10 s, of a loudspeaker throughout the duration of the test.
14 © ISO 2010 – All rights reserved

5.6.2.4 Final measurements
Measure the frequency response in accordance with 5.1.5 or, if applicable, 5.1.6.
Measure the rated impedance in accordance with 5.3.
5.6.3 Requirements
The RMS current consumption of a specimen that incorporates protective devices shall not be reduced by
more than 25 % at any time during the conditioning.
At the end of the recovery period,
a) the frequency response does not deviate from the one measured before the test by more than ± 3 dB,
between and including 500 Hz and 8 kHz; and
b) the frequency response complies with the frequency response performance requirement in 4.2.
The lowest impedance modulus is not lower than 80 % of the impedance specified by the manufacturer.
5.7 Dry heat (operational)
5.7.1 Object of the test
To demonstrate the ability of the specimen to function correctly at high ambient temperatures, which can
occur for short periods in the service environment.
5.7.2 Test procedure
5.7.2.1 General
Use the test apparatus and perform the procedure specified in IEC 60068-2-2, Test Bb, and in 5.7.2.2 to
5.7.2.5.
5.7.2.2 State of specimen during conditioning
Maintain the specimen in the quiescent state during the conditioning, except during the last hour, when it shall
be supplied with a simulated program signal at half the rated noise voltage.
5.7.2.3 Conditioning
Apply the following conditioning:
⎯ temperature: (55 ± 2) °C for type A or (70 ± 2) °C for type B;
⎯ duration: 16 h.
NOTE Test Bb specifies rates of change of temperature of < 1 °C/min for the transitions to and from the conditioning
temperature.
5.7.2.4 Measurements during conditioning
Monitor the specimen for audible output during the final hour of the conditioning.
5.7.2.5 Final measurements
Measure the frequency response of the specimen as specified in 5.1.5 or, if applicable, 5.1.6 after the
recovery period speci
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