SIST-TS CEN/TS 1793-4:2004

Road traffic noise reducing devices - Test method for determining the acoustic performance - Part 4: Intrinsic characteristics - In situ values of sound diffraction

This document describes a test method for determining the intrinsic characteristics of sound diffraction of added devices installed on the top of traffic noise reducing devices. The test method prescribes measurements of the sound pressure level at several reference points near the top edge of a noise reducing device with and without the added device installed on its top. The effectiveness of the added device is calculated as the difference between the measured values with and without the added devices, correcting for any change in height.
The test method is intended for the following applications:
· preliminary qualification, outdoors or indoors, of added devices to be installed on noise reducing devices;
· determination of sound diffraction index difference of added devices in actual use;
· comparison of design specifications with actual performance data after the completion of the construction work;
· verification of the long term performance of added devices (with a repeated application of the method).
The test method can be applied both in situ and on samples purposely built to be tested using the method described here.
Results are expressed as a function of frequency, in one-third octave bands between 100 Hz and 5 kHz. If it is not possible to get valid measurements results over the whole frequency range indicated, the results should be given in the restricted frequency range and the reasons of the restriction(s) should be clearly reported. A single-number rating is calculated from frequency data.
For indoors measurements see annex B.

Lärmschutzeinrichtungen an Straßen - Prüfverfahren zur Bestimmung der akustischen Eigenschaften - Teil 4: Produktspezifische Merkmale - Insitu-Werte der Schallbeugung

Dispositifs de réduction du bruit du trafic routier - Méthode d'essai pour la détermination des performances acoustiques - Partie 4 : Caractéristiques intrinseques - Valeurs in situ de la diffraction acoustique

Le présent document décrit une méthode d'essai permettant de déterminer les caractéristiques intrinseques de la diffraction acoustique des dispositifs additionnels installés au sommet des dispositifs de réduction du bruit. La méthode d'essai prescrit des mesures du niveau de pression acoustique en différents points de référence situés pres du bord supérieur du dispositif de réduction du bruit, avec et sans dispositif additionnel installé au sommet. L'efficacité du dispositif additionnel est calculée comme étant la différence entre les valeurs mesurées avec et sans dispositifs additionnels, avec une correction pour tout changement de hauteur.
La méthode d'essai est destinée aux applications suivantes :
   la qualification préliminaire, a l'extérieur ou a l'intérieur de bâtiments, des dispositifs additionnels a installer sur les dispositifs de réduction du bruit ;
   la détermination de la différence d'indice de diffraction acoustique des dispositifs additionnels actuellement utilisés ;
   la comparaison des spécifications de conception avec des données de performance réelles de l'ouvrage achevé ;
   la vérification des performances a long terme de dispositifs additionnels (par l'application répétée de la méthode).
La méthode d'essai peut etre appliquée in situ et sur des échantillons construits spécifiquement pour etre soumis a essai selon la méthode décrite dans le présent document.
Les résultats sont exprimés en fonction de la fréquence, par bandes de tiers d'octave pour la plage comprise entre 100 Hz et 5 kHz. S'il est impossible d'obtenir des résultats de mesure valables sur toute la plage de fréquence spécifiée, il convient de donner les résultats pour la plage de fréquence réduite et de consigner clairement les raisons de la ou des restrictions. Un indice unique d'évaluation est calculé a partir des données de fréquence.
Voir l'annexe B pour les mesures a l'intérieur.

Protihrupne ovire za cestni promet - Preskusna metoda za ugotavljanje akustičnih lastnosti - 4. del: Bistvene lastnosti - Terenske vrednosti difrakcije zvoka

General Information

• Status: Withdrawn
• Publication Date: 31-May-2004
• Withdrawal Date: 29-Mar-2015
• ICS: 17.140.30 - Noise emitted by means of transport
• ICS: 93.080.30 - Road equipment and installations
• Technical Committee: OCE - Road equipment
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 27-Mar-2015
• Due Date: 19-Apr-2015
• Completion Date: 30-Mar-2015
• Directive: 89/106/EEC - Construction products
• Ref Project: CEN/TS 1793-4:2003 - Road traffic noise reducing devices - Test method for determining the acoustic performance - Part 4: Intrinsic characteristics - In situ values of sound diffraction

Relations

• Replaced By: SIST EN 1793-4:2015 - Road traffic noise reducing devices - Test method for determining the acoustic performance - Part 4: Intrinsic characteristics - In situ values of sound diffraction
• Effective Date: 01-May-2015
• Parent: SIST EN 1793-1:1999 - Road traffic noise reducing devices - Test method for determining the acoustic performance - Part 1: Intrinsic characteristics of sound absorption
• Effective Date: 22-Dec-2008

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TS CEN/TS 1793-4:2004
01-junij-2004
3URWLKUXSQHRYLUH]DFHVWQLSURPHW3UHVNXVQDPHWRGD]DXJRWDYOMDQMHDNXVWLþQLK
ODVWQRVWLGHO%LVWYHQHODVWQRVWL7HUHQVNHYUHGQRVWLGLIUDNFLMH]YRND
Road traffic noise reducing devices - Test method for determining the acoustic
performance - Part 4: Intrinsic characteristics - In situ values of sound diffraction
Lärmschutzeinrichtungen an Straßen - Prüfverfahren zur Bestimmung der akustischen
Eigenschaften - Teil 4: Produktspezifische Merkmale - Insitu-Werte der Schallbeugung
Dispositifs de réduction du bruit du trafic routier - Méthode d'essai pour la détermination
des performances acoustiques - Partie 4 : Caractéristiques intrinseques - Valeurs in situ
de la diffraction acoustique
Ta slovenski standard je istoveten z: CEN/TS 1793-4:2003
ICS:
17.140.30 Emisija hrupa transportnih Noise emitted by means of
sredstev transport
93.080.30 Cestna oprema in pomožne Road equipment and
naprave installations
SIST-TS CEN/TS 1793-4:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN/TS 1793-4:2004

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SIST-TS CEN/TS 1793-4:2004
TECHNICAL SPECIFICATION
CEN/TS 1793-4
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
December 2003
ICS 17.140.30, 93.080.30
English version
Road traffic noise reducing devices - Test method for
determining the acoustic performance - Part 4: Intrinsic
characteristics - In situ values of sound diffraction
Dispositifs de réduction du bruit du trafic routier – Méthode Lärmschutzeinrichtungen an Straßen - Prüfverfahren zur
d’essai pour la détermination des performances Bestimmung der akustischen Eigenschaften - Teil 4:
acoustiques – Partie 4 : Caractéristiques intrinsèques – Produktspezifische Merkmale - Insitu-Werte der
Valeurs in situ de la diffraction acoustique Schallbeugung
This Technical Specification (CEN/TS) was approved by CEN on 6 June 2003 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available. It
is permissible to keep conflicting national standards in force (in parallel to the CEN/TS) until the final decision about the possible
conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 1793-4:2003 E
worldwide for CEN national Members.

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Contents
Foreword.4
Introduction .5
1 Scope .4
2 Normative references .5
3 Definitions and symbols .5
3.1 Definitions.5
3.2 Symbols .6
4 Diffraction index difference measurements.7
4.1 General principle.7
4.2 Dimensions and specifications .7
4.3 Positions of the sound source .8
4.4 Position of the microphones .8
4.5 Free-field measurements .9
4.6 Measured quantity .14
4.7 Measuring equipment.16
4.8 Data processing .18
4.9 Positioning of the measuring equipment .21
4.10 Diffraction index difference .22
DL
4.11 Single-number rating of diffraction index difference .22DDDI
4.12 Sample surface and meteorological conditions.23
4.13 Measuring procedure .23
4.14 Test report .24
Annex A (Informative) Definition and usage of the MLS signal.26
Annex B (Informative) Indoor measurements for product qualification.28
Annex C (Informative) Bibliography .29
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Foreword
This document (CEN/TS 1793-4:2003) has been prepared by Technical Committee CEN/TC 226 “Road
equipment”, the secretariat of which is held by AFNOR.
It should be read in conjunction with :
EN 1793-1, Road traffic noise reducing devices - Test method for determining the acoustic performance –
Part 1 : Intrinsic characteristics of sound absorption
EN 1793-2, Road traffic noise reducing devices - Test method for determining the acoustic performance –
Part 2 : Intrinsic characteristics of airborne sound insulation
EN 1793-3, Road traffic noise reducing devices - Test method for determining the acoustic performance –
Part 3 : Normalized traffic noise spectrum
CEN/TS 1793-5, Road traffic noise reducing devices - Test method for determining the acoustic performance –
Part 5: Intrinsic characteristics – In situ values of sound reflection and airborne sound insulation.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Czech Republic, Denmark,
Finland, France, Germany, Greece, Hungary Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway,
Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
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Introduction
Part of the market of road traffic noise reducing devices is constituted of products to be added on the top of noise
reducing devices and intended to contribute to sound attenuation acting primarily on the diffracted sound field.
These products will be called added devices. This standard has been developed to specify a test method for
determining the acoustic performance of added devices.
The test method can be applied in situ, i.e. where the traffic noise reducing devices and the added devices are
installed. The method can be applied without damaging the traffic noise reducing devices or the added devices.
The method can be used to qualify products before the installation along roads as well as to verify the compliance
of installed added devices to design specifications. Repeated application of the method can be used to verify the
long term performance of added devices.
NOTE – This method could be used to qualify added devices for other applications, e.g. to be installed along railways or nearby
industrial sites. In this case special care has to be taken into account in considering the location of the noise sources and the
single-number ratings should be calculated using an appropriate spectrum.
No other national or international standard exists about the subject of this standard.
1 Scope
This document describes a test method for determining the intrinsic characteristics of sound diffraction of added
devices installed on the top of traffic noise reducing devices. The test method prescribes measurements of the
sound pressure level at several reference points near the top edge of a noise reducing device with and without the
added device installed on its top. The effectiveness of the added device is calculated as the difference between the
measured values with and without the added devices, correcting for any change in height.
The test method is intended for the following applications:
• preliminary qualification, outdoors or indoors, of added devices to be installed on noise reducing devices;
• determination of sound diffraction index difference of added devices in actual use;
• comparison of design specifications with actual performance data after the completion of the construction work;
• verification of the long term performance of added devices (with a repeated application of the method).
The test method can be applied both in situ and on samples purposely built to be tested using the method
described here.
Results are expressed as a function of frequency, in one-third octave bands between 100 Hz and 5 kHz. If it is not
possible to get valid measurements results over the whole frequency range indicated, the results shall be given in
the restricted frequency range and the reasons of the restriction(s) shall be clearly reported. A single-number rating
is calculated from frequency data.
For indoor measurements see Annex B.
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2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate place in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the
publication applies.
EN 1793-3: 1997, Road traffic noise reducing devices - Test method for determining the acoustic performance -
Part 3: Normalized traffic noise spectrum.
EN 60651: 1979, Sound level meters.
3 Definitions and symbols
3.1 Definitions
For the purpose of this standard the following definitions apply:
3.1.1
structural elements
those elements whose primary function is to support or hold in place acoustic elements
3.1.2
acoustical elements
those elements whose primary function is to provide the acoustic performance of the device
3.1.3
noise barrier
noise reducing device which obstructs the direct transmission of airborne sound emanating from road traffic
3.1.4
added device
acoustic element added on the top of a noise reducing device and intended to contribute to sound attenuation
acting primarily on the diffracted sound field
3.1.5
roadside exposure
The use of the product as a noise reducing device installed alongside roads
3.1.6
diffraction index
The result of a sound diffraction test described by formula (1). DI refers to measurements on a reflective
refl
reference wall. DI refers to measurements on an absorptive reference wall. DI refers to in situ measurements
abs situ
3.1.7
diffraction index difference
difference between the results of sound diffraction tests on the same reference wall with and without an added
device on the top, described by formula (4)
3.1.8
test construction
construction on which the added device is placed. For in situ measurements it is an installed noise reducing device;
for qualification tests it is a reference wall (see 4.2)
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3.1.9
reference plane of the test construction
the vertical plane passing through the midpoint of the top edge of the construction (reference wall or installed noise
reducing device) on which the added device has to be placed (see figures 1, 2, 4, 5, 8)
3.1.10
reference height of the test construction without the added device, h
ref,0
height of the highest point of the test construction in relation to the surrounding ground surface. This highest point
is not necessarily lying in the plane of longitudinal symmetry of the reference test construction, if this symmetry
exists (figure 1)
3.1.11
reference height of the test construction with the added device on the top, h
ref,add
height of the highest point of the added device installed on the test construction in relation to the surrounding
ground surface. This highest point is not necessarily lying in the plane of longitudinal symmetry of the reference
test construction, if this symmetry exists (figure 4)
3.1.12
free-field measurement for diffraction index measurements
Measurement carried out placing the loudspeaker and the microphone as specified in 4.5 and 4.8 without any
obstacle, including the test construction with or without added device, between them (see for example figure 7)
3.1.13
adrienne temporal window
the composite temporal window described in 4.5.5
3.1.14
background noise
noise coming from sources other than the source emitting the test signal
3.1.15
signal-to-noise ratio, S/N
The difference in decibels between the level of the test signal and the level of the background noise at the moment
of detection of the useful event (within the Adrienne temporal window)
3.1.16
impulse response
the time signal at the output of a system when a Dirac function is applied to the input. The Dirac function, also
called d function, is the mathematical idealisation of a signal infinitely short in time that carries a unit amount of
energy
3.2 Symbols
DI is the diffraction index for the reflective reference wall without the added device (dB),
0,refl
DI is the diffraction index for the reflective reference wall with the added device (dB),
ad,refl
DI is the diffraction index for the absorptive reference wall without the added device (dB),
0,abs
DI is the diffraction index for the absorptive reference wall with the added device (dB),
ad,abs
DI is the diffraction index for the in situ test construction without the added device (dB),
0,situ
DI is the diffraction index for the in situ test construction with the added device (dB).
ad,situ
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4 Diffraction index difference measurements
4.1 General principle
The sound source emits a transient sound wave that travels toward the noise reducing device under test and is
partly reflected, partly transmitted and partly diffracted by it. The microphone placed on the other side of the noise
reducing device receives both the transmitted sound pressure wave travelling from the sound source through the
noise reducing device and the sound pressure wave diffracted by the top edge of the noise reducing device under
test (for the test to be meaningful the diffraction from the vertical edges of the test construction shall be sufficiently
delayed in order to be outside the Adrienne temporal window). If the measurement is repeated without the added
device and the test construction between the loudspeaker and the microphone, the direct free-field wave can be
acquired. The power spectra of the direct and the top-edge diffracted components, corrected to take into account
the path length difference of the two components, give the basis for calculating the diffraction index.
The final diffraction index shall be a weighted average of the diffraction indices measured at different points (see
Figures 1 to 6).
When the test method is applied in situ, the measurement procedure and diffraction index calculation shall be
carried out two times, with and without the added device placed on the test construction.
When the test method is applied on samples purposely built to be tested according to the present standard, the
added device shall be subsequently placed on the top of two reference walls (see 4.2) and the measurement
procedure and diffraction index calculation shall be carried out for both walls, with and without the added device on
the top.
The measurement must take place in an essentially free field in the direct surroundings of the device, i.e. a field
free from reflections coming from surfaces other than the surface of the device under test. For this reason, the
acquisition of an impulse response having peaks as sharp as possible is recommended: in this way, the reflections
coming from other surfaces than the tested device can be identified from their delay time and rejected.
4.2 Dimensions and specifications
4.2.1 Added devices
The added device shall have a minimum length L of 10 m. The reference wall shall have a minimum length L of
d b
10 m and a minimum height of 4 m. The reference wall shall be vertical, flat and fixed firmly and without any air
gaps on a supporting construction (foundation, floor etc.). The top surface of the supporting construction shall be
level with the surrounding ground surface.
The maximum size of the added device measured perpendicularly from the reference plane either in the direction
of the source or in the direction of the microphones shall not exceed a value of 0,75 m (see figure 8).
4.2.2 Reference walls
Two versions of the reference wall shall be used in the tests:
A A reflective reference wall, constructed of homogeneous concrete panels with a mass per unit area of at least
2
100 kg/m and a smooth surface finish. The wall shall be free of air leaks and shall have a thickness not greater
than 0,20 m.
B An absorptive reference wall, constructed of concrete panels as mentioned under A, lined on the source side
with an absorptive layer of 50 mm fibrous material having a flow resistivity value between 2000 and 4000
2
Pa⋅s/m .
4.2.3 In situ tests
When applying the test method in situ on existing noise reducing devices, with the intention of obtaining results
valid over the entire frequency range specified in 4.6, the test construction shall satisfy the requirements in 4.2.2.
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If these requirements cannot be fulfilled by the existing noise reducing device, the obtained results shall only be
valid over a restricted frequency range (see 4.8.7) and for the type of noise reducing device being tested.
4.3 Positions of the sound source
Two angles of incidence, 90° and 45°, shall be used (see figures 2 and 5).
For execution of the diffraction test at a right angle to the test construction the sound source shall be placed as
follows (see figures 1, 2, 4 and 5):
• in the vertical plane containing the perpendicular bisector plane to the reference plane;
• horizontally: at 2 m distance from the reference plane of the test construction;
• vertically: in relation to the reference height h of the test construction,
ref
for the obligatory source position S1: centre of the source 0,50 m lower than h ;
ref
for the additional source position S2: centre of the source 0,15 m lower than h ;
ref
for the additional source position S3: centre of the source 0,65 m lower than h ;
ref
• oriented towards the microphone position M2 (see 4.4 and figures 1 and 3).
For execution of the diffraction test at an angle of 45° with the reference plane of the test construction the sound
source shall be placed as follows (see Figures 2 and 5):
• in a vertical plane that makes an angle of 45° with the reference plane of the test construction, passing through
its mid-point;
• horizontally: at 2 m distance from the reference plane of the test construction;
• vertically in relation to the reference height h of the test construction,
ref
for the obligatory source position S4: centre of the source 0,50 m lower than h ;
ref
for the additional source position S5:centre of the source 0,15 m lower than h ;
ref
for the additional source position S6:centre of the source 0,65 m lower than h ;
ref
• oriented towards the microphone position M8 (see 4.4 and figures 2 and 3).
4.4 Position of the microphones
For execution of the diffraction test at a right angle to the test construction the microphones shall be placed as
follows (see Figures 1 to 6):
• in the vertical plane containing the perpendicular bisector plane to the reference plane;
• horizontally: at 2 m distance from the reference plane of the test construction;
• vertically in relation to the reference height h of the test construction,
ref
for the obligatory microphone positions M1, M2, M3 and M4:
- microphone M1: 0,75 m higher;
- microphone M2: 0,50 m higher;
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- microphone M3: equal to the reference height;
- microphone M4: 0,50 m lower;
for the additional microphone positions 5 and 6:
- microphone M5: 0,25 m higher;
- microphone M6: 0,25 m lower.
• making an angle in the horizontal plane so as to be oriented toward the sound source.
For execution of the diffraction test at an angle of 45° with the reference plane of the test construction the
microphones shall be placed as follows (see Figures 1, 2, 3, 5 and 6):
• in a vertical plane that makes an angle of 45° with the reference plane of the test construction, passing through
its mid-point;
• horizontally: at 2 m distance from the longitudinal axis of the test construction;
• vertically in relation to the reference height h of the test construction,
ref
for the obligatory microphone positions M7, M8, M9 and M10:
- microphone M7: 0,75 m higher;
- microphone M8: 0,50 m higher;
- microphone M9: equal to the reference height;
- microphone M10: 0,50 m lower.
for the additional microphone positions 10, 11 and 12:
- microphone M11: 0,25 m higher;
- microphone M12: 0,25 m lower.
• making an angle in the horizontal plane so as to be oriented toward the sound source.
4.5 Free-field measurements
For each set of measurements done placing the sound source according to 4.3 (90° and 45°), at least one free-field
measurement shall be carried out, placing the microphone at relative distances from the sound source as in the
position S1-M2 for normal incidence measurements and in position S4-M8 for measurements at an angle of 45°
(see for example Figure 7). A whole set of measurements shall be carried out within two hours. Otherwise a new
free-field measurement has to be carried out.
No obstacle shall be present within a distance of 3 m from the microphone.
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1 Reference plane
Figure 1 - Source and microphone positions in a vertical cross section of the test construction without
added device.
1 Reference plane
Figure 2 - Source and microphone positions in a top view of the test construction without added device.
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2 m
M1 M7
0,25 m
M2 M8
M5 M11
M3 M9
M6 M12
M4 M10
h
ref,0
Figure 3 - Microphone positions in a vertical back view from receiver side of the test construction without
added device.
1 Reference plane
2 Added device
Figure 4 - Source and microphone positions in a vertical cross section of the test construction with added
device.
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1 Reference plane
2 Added device
Figure 5 - Source and microphone positions in a top view of the test construction with added device.
1 Added device
Figure 6 - Microphone positions in a vertical back view from receiver side of the test construction with
added device.
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2 m 2 m
0,25 m
M2
0,50 m
S1
h
ref
Figure 7 - Source and microphone positions for the free-field measurement in a vertical cross section
(example given for source position S1 and microphone position M2).
1 Reference plane
2 Added device
Figure 8 - Maximum size of the added device.
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4.6 Measured quantity
The expression used to compute the diffraction index DI as a function of frequency, in one-third octave bands, is:
2
 n 
 
2 d
k
   
F[]h (t)w (t) df
∑
dk dk
∫
 
d
 k=1 ŁiłDf 
j
DI =-10lg
 
j
2
n ⋅ F[]h (t)w (t) df
 
i i
∫
Df 
j
 
 
where:
h(t) is the incident reference component of the free-field impulse response;
i
h (t) is the component of the impulse response diffracted by the top edge of the test construction and received
d,k
at the k-th measurement point (k=1…n);
d is the geometrical spreading correction factor for the reference free-field impulse response;
i
d is the geometrical spreading correction factor for the impulse response diffracted by the top edge of the
k
test construction and received at the k-th measurement point (k=1…n);
w(t) is the incident reference free-field component time window (Adrienne temporal window);
i
w (t) is the time window (Adrienne temporal window) for the component of the impulse response diffracted by
dk
the top edge of the test construction and received at the k-th measurement point (k=1…n);
F is the symbol of the Fourier transform;
j is the index of the one-third octave frequency bands (between 100 Hz and 5 kHz);
Df is the width of the j-th one-third octave frequency band (between 100 Hz and 5 kHz);
j
n = 8, …, 36 is the number of measurement points, depending on the use of the obligatory positions only or of the
obligatory and optional positions.
The geometrical spreading correction factors d and d are written in metres in table 1.
i k
The diffraction index shall be calculated two times:
• for the test construction without added device (DI );
0
• for the test construction with added device (DI );
ad
For each set of measurements, at least one free-field measurement shall be carried out, as described in 4.5.
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Table 1 - Values of the geometrical spreading correction factors in formula (1).
d 4,12 S1
i
k 123456
d 4,20 4,12 4,06 4,12 4,08 4,08
k
d 4,08 S2
i
k 123456
d 4,11 4,08 4,06 4,08 4,07 4,07
k
d 4,45 S3
i
k 123456
d 4,85 4,45 4,06 4,45 4,16 4,16
k
d 5,74 S4
i
k 7 8 9 10 11 12
d 5,80 5,74 5,70 5,74 5,71 5,71
k
d 5,72 S5
i
k 7 8 9 10 11 12
d 5,74 5,72 5,70 5,72 5,70 5,70
k
d 5,99 S6
i
k 7 8 9 10 11 12
d 6,31 5,99 5,70 5,99 5,77 5,77
k
NOTE - the geometrical spreading correction factors previously specified may be inappropriate for added devices which can
give rise to multiple reflections inside them (see figure 9).
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SIST-TS CEN/TS 1793-4:2004
CEN/TS 1793-4:2003 (E)
1 Reference plane
2 Added device
Figure 9 - Vertical cross section of a test construction with an added device giving rise to multiple
reflections.
4.7 Measuring equipment
4.7.1 Components of the measuring system
The measuring equipment shall comprise: an electro-acoustic system, consisting of an electrical signal generator, a
power amplifier and a loudspeaker, a microphone with its microphone amplifier and a signal analyser capable of
performing transformations between the time domain and the frequency domain.
NOTE - Part of these devices can be integrated into a frequency analyser or a personal computer equipped with specific add-on
board(s).
The essential components of the measuring system are shown in Figure 10.
The complete measuring system shall meet the requirements of at least a type 1 instrument in accordance with
EN 60651.
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SIST-TS CEN/TS 1793-4:2004
CEN/TS 1793-4:2003 (E)
4.7.3 Test signal
The test signal shall co
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