ETSI ES 202 396-1 V1.9.1 (2023-05)

ETSI ES 202 396-1 V1.9.1 (2023-05)






ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Speech quality performance
in the presence of background noise;
Part 1: Background noise simulation technique
and background noise database

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2 ETSI ES 202 396-1 V1.9.1 (2023-05)

Reference
RES/STQ-308
Keywords
noise, performance, quality, speech
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ETSI

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3 ETSI ES 202 396-1 V1.9.1 (2023-05)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definition of terms, symbols and abbreviations . 9
3.1 Terms . 9
3.2 Symbols . 9
3.3 Abbreviations . 9
4 Overview of existing methods for realistic sound reproduction. 9
4.1 Introduction . 9
4.2 Surround Sound Techniques. 10
®
4.3 IOSONO . 11
4.4 Eidophonie . 11
4.5 Four-loudspeaker arrangement for playback of binaurally recorded signals . 12
4.6 NTT Background-Noise Database . 13
4.7 General conclusions . 13
5 Recording arrangement . 14
5.1 Binaural recordings . 14
5.2 Equalization procedure . 14
6 Loudspeaker Setup for Background Noise Simulation . 16
6.1 Test Room Requirements . 16
6.2 Loudspeaker Positioning . 17
6.3 Equalization and Calibration . 18
6.3.1 Overview . 18
6.3.2 Separate equalization for each of the four loudspeakers . 18
6.3.3 Separate level adjustment for each loudspeaker . 20
6.3.4 Equalization for the two left-hand and the two right-hand loudspeakers . 20
6.3.5 Equalization and level adjustment for the subwoofer . 21
6.3.6 Delay compensation . 21
6.3.7 Overall equalization for all loudspeakers . 22
6.3.8 Troubleshooting failed equalizations . 23
6.3.9 Automated equalization and calibration procedure . 23
6.4 Accuracy of the reproduction arrangement . 23
6.4.0 Introduction. 23
6.4.1 Comparison between original sound field and simulated sound field . 23
6.4.2 Displacement of the test arrangement in the simulated sound field . 25
6.4.3 Transmission of background noise: Comparison of terminal performance in the original sound field
and the simulated sound field . 27
6.5 Simulation of additional acoustic conditions . 30
7 Background Noise Simulation in cars . 31
7.1 General setup . 31
7.2 Recording arrangement . 32
7.2.0 Introduction. 32
7.2.1 Recording setup with the terminal's microphone . 32
7.2.2 Recording setup with a pair of cardioid microphones. 33
7.3 Equalization and calibration with the terminal's microphone . 33
7.3.1 Overview . 33
7.3.2 Separate equalization for each of the four loudspeakers . 34
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4 ETSI ES 202 396-1 V1.9.1 (2023-05)
7.3.3 Separate level adjustment for each loudspeaker . 36
7.3.4 Equalization for the two front and the two rear loudspeakers . 36
7.3.5 Equalization and level adjustment for the subwoofer . 37
7.3.6 Delay adjustment . 37
7.3.7 Overall equalization . 38
7.3.8 Troubleshooting failed equalizations . 38
7.4 Equalization and Calibration with a pair of cardioid microphones . 38
7.4.1 Overview . 38
7.4.2 Pair-wise equalization for the left-hand loudspeakers . 39
7.4.3 Separate level adjustment for the left-hand loudspeakers . 41
7.4.4 Pair-wise equalization and separate level adjustment for the right-hand loudspeakers . 41
7.4.5 Equalization and level adjustment for the subwoofer . 41
7.4.6 Delay compensation . 41
7.4.7 Overall equalization . 42
7.4.8 Troubleshooting failed equalizations . 42
7.5 Accuracy of the reproduction arrangement . 43
7.5.1 Comparison between original sound field and simulated sound field . 43
7.5.2 Transmission of background noise: Comparison of terminal performance in the original sound field
and the simulated sound field . 44
7.6 Automated equalization and calibration procedure . 46
8 Background Noise Database . 46
8.0 Introduction . 46
8.1 Binaural signals . 47
8.2 Binaural signals identical to the background noise recordings provided in ETSI TS 103 224 . 49
8.3 Stereophonic signals . 50
Annex A (informative): Comparison of Tests in Sending Direction and D-Values Conducted
in Different Rooms . 51
A.0 Introduction . 51
A.1 Test Setup . 51
A.2 Results of the Tests . 52
A.2.0 Introduction . 52
A.2.1 Sending Frequency Response Characteristics and SLR . 52
A.2.2 D-Value with Pink Noise . 52
A.2.3 D-Value with Cafeteria Noise . 53
A.3 Conclusions . 53
Annex B (informative): Graphs of test results in Annex A . 54
History . 62

ETSI

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5 ETSI ES 202 396-1 V1.9.1 (2023-05)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations
pertaining to these essential IPRs, if any, are publicly available for ETSI members and non-members, and can be
found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to
ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the
ETSI Web server (https://ipr.etsi.org/).
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essential to the present document.
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Foreword
This ETSI Standard (ES) has been produced by ETSI Technical Committee Speech and multimedia Transmission
Quality (STQ).
The present document is part 1 of a multi-part deliverable covering Speech and multimedia Transmission Quality
(STQ); Speech quality performance in the presence of background noise, as identified below:
ETSI ES 202 396-1: "Background noise simulation technique and background noise database";
ETSI EG 202 396-2: "Background noise transmission - Network simulation - Subjective test database and results";
ETSI EG 202 396-3: "Background noise transmission - Objective test methods".
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Background noise is present in most of the conversations today. Background noise may impact the speech
communication performance to terminal and network equipment significantly. Therefore testing and optimization of
such equipment is necessary using realistic background noises. Furthermore reproducible conditions for the tests are
required which can be guaranteed only under lab type condition.
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6 ETSI ES 202 396-1 V1.9.1 (2023-05)
The present document addresses this issue by describing a methodology for recording and playback of background
noises under well-defined and calibratable conditions in a lab-type environment. Furthermore a database with real
background noises is included.
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7 ETSI ES 202 396-1 V1.9.1 (2023-05)
1 Scope
The quality of background noise transmission is an important factor, which significantly contributes to the perceived
overall quality of speech. Both existing and, even more notably, the new generation of terminals, networks and system
configurations, including broadband services, can be greatly improved when designed properly, with consideration and
presence of background noise. The present document:
• describes a noise simulation environment using realistic background noise scenarios for laboratory use;
• contains a database including the relevant background noise samples for subjective and objective evaluation.
The present document provides information about the recording techniques needed for background noise recordings and
discusses the advantages and drawbacks of existing methods. Additionally, the present document describes the
requirements for laboratory conditions. The loudspeaker setup and the loudspeaker calibration and equalization
procedure are described. The simulation environment specified can be used for the evaluation and optimization of
terminals and of complex configurations including terminals, networks and other configurations. The main application
areas should be: office, home and car environment.
The setup and database as described in the present document are applicable for:
• Objective performance evaluation of terminals in different (simulated) background noise environments.
• Speech processing evaluation by using the pre-processed speech signal in the presence of background noise,
recorded by a terminal.
• Subjective evaluation of terminals by performing conversational tests, specific double talk tests or talking and
listening tests in the presence of background noise.
• Subjective evaluation in third party listening tests by recording the speech samples of terminals in the presence
of background noise.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
[1] Recommendation ITU-T P.57: "Artificial ears".
[2] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".
[3] ETSI TS 103 224: "Speech and multimedia Transmission Quality (STQ); A sound field
reproduction method for terminal testing including a background noise database".
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8 ETSI ES 202 396-1 V1.9.1 (2023-05)
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Surround Sound Past, Present, and Future: "A history of multichannel audio from mag stripe to
Dolby Digital", Joseph Hull - Dolby Laboratories Inc.
[i.2] AES preprint 3332 (1992): "Improved Possibilities of Binaural Recording and Playback
Techniques", K. Genuit, H.W. Gierlich; U. Künzli.
[i.3] AES preprint 3732 (1993): "A System for the Reproduction Technique for Playback of Binaural
Recordings", N. Xiang, K. Genuit, H.W. Gierlich.
[i.4] NTTAT Database: "Ambient Noise Database CD-ROM".
[i.5] ISO 11904-1: "Acoustics - Determination of sound immission from sound sources placed close to
the ear - Part 1: Technique using a microphone in a real ear (MIRE technique)".
[i.6] J. Blauert: "The psychophysics of human sound localization", Spatial Hearing.
[i.7] Void.
[i.8] Void.
[i.9] Recommendation ITU-T P.340: "Transmission characteristics and speech quality parameters of
hands-free terminals".
[i.10] Recommendation ITU-T P.64: "Determination of sensitivity/frequency characteristics of local
telephone systems".
[i.11] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".
[i.12] Genuit, K.: "A Description of the Human Outer Ear Transfer Function by Elements of
Communication Theory (No. B6-8)".
th
NOTE: Proceedings of the 12 International Congress on Acoustics. Toronto published on behalf of the
th
Technical Program Committee by the Executive Committee of the 12 International Congress on
Acoustics.
[i.13] IEC 60050-722: "International Electrotechnical Vocabulary - Chapter 722: Telephony".
[i.14] "Wellenfeldsynthese - Eine neue Dimension der 3D-Audiowiedergabe"; Fernseh- und
Kino-Technik, Nr. 11/2002, pp. 735-738.
[i.15] N.Lee: "IOSONO" Computers in Entertainment, volume 2, issue 3 (2004).
[i.16] P. Scherer: "Ein neues Verfahren der raumbezogenen Stereophonie mit verbesserter Übertragung
der Rauminformation"; Rundfunktechnische Mitteilungen, 1977, pp. 196-204.
[i.17] Void.
[i.18] ETSI TS 151 010-1: "Digital cellular telecommunications system (Phase 2+) (GSM); Mobile
Station (MS) conformance specification; Part 1: Conformance specification (3GPP TS 51.010-1)".
[i.19] Void.
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9 ETSI ES 202 396-1 V1.9.1 (2023-05)
[i.20] ETSI TR 126 921: "Universal Mobile Telecommunications System (UMTS); LTE; 5G;
Investigations on ambient noise reproduction systems for acoustic testing of terminals (3GPP
TR 26.921)".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
cross-talk: appearance of undesired energy in a channel, owing to the presence of a signal in another channel, caused
by, for example, induction, conduction or non-linearity
NOTE: See IEC 60050-722 [i.13].
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
CD Compact Disc
DF Diffuse Field
EQ Equalization
FF Free Field
FFT Fast Fourier Transform
FIR Finite Impulse Response
HATS Head And Torso Simulator
ID Independent of Direction
IIR Infinite Impulse Response
MIRE Microphone In Real Ear
MRP Mouth Reference Point
NTT Nippon Telegraph and Telephone corporation
SLR Send Loudness Rating
VHF Very High Frequency
4 Overview of existing methods for realistic sound
reproduction
4.1 Introduction
In general the existing methods for close to original sound recording and reproduction aimed for different applications:
• Techniques intending to reproduce the actual sound field.
• Techniques providing hearing adequate (ear related) signals in the human ear canal.
• Techniques generating artificial acoustical environments.
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Within this clause the different methods are briefly described and their applicability for close to original sound-filed
reproduction is discussed. A variety of methods have been studied, in the following a summary of the most important
ones relevant to the present document is given. The different methods were analysed on the basis of the following
requirements:
• The background noise recording technique should be:
- easy to use;
- easy to calibrate;
- capable of wideband recording;
- available at reasonable costs;
- mostly compatible to existing standards and procedures used in telecommunications testing;
- applicable to different environments (at least office, home and car).
• The background noise simulation arrangement should:
- be easy to setup;
- not require any specific acoustical treatment for the simulation requirement;
- provide a mostly realistic background noise simulation for all typical background noises faced with in
telecommunication applications;
- be easy to calibrate;
- be mostly insensitive against the positioning of (test)-objects in the simulated sound field;
- be applicable to all typical terminals used in telecommunication;
- be available at reasonable costs.
4.2 Surround Sound Techniques
The basics
...