Scope
IEC 60268-16:2011
Speech Transmission Index Measurement
This test method provides an objective measure of speech intelligibility in acoustic environments using the Speech Transmission Index (STI) method. STI quantifies how well speech is transmitted through an acoustic space, accounting for noise, reverberation, and frequency distortion. The measurement is critical for evaluating communication effectiveness in public address systems, conference rooms, classrooms, and other speech-critical environments. Venues with high standards for speech clarity use this method to verify system performance and acoustic suitability. ISO 17025 accreditation ensures reliable assessment of speech intelligibility compliance with design standards.
What it measures
- Speech Transmission Index (STI) value (0-1 scale)
- Modulation transfer function across frequency bands
- Speech intelligibility rating and quality assessment
- Impact of noise and reverberation on speech clarity
- Communication effectiveness and auditory conditions
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DIN EN ISO 3382-2
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BS EN ISO 3382-2
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NF EN ISO 3382-2
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UNI EN ISO 3382-2
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UNE EN ISO 3382-2
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NEN EN ISO 3382-2
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DIN EN ISO 1996-2
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BS EN ISO 1996-2
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NF EN ISO 1996-2
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UNI EN ISO 1996-2
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UNE EN ISO 1996-2
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NEN EN ISO 1996-2
1,868
Accredited labs
20
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Showing 126–150 of 393 labs
Devonport Royal Dockyard
Active
BS 4206:1967 (superseded)
ISO 5173
ISO 7438
BS EN ISO 9606-2:2004
BS 131-5:1965
+ 3 more
Diatec Diagnostics
Active
AUDIOMETRIC EQUIPMENT
Attenuator linearity
Microphones
EAR SIMULATORS
Class LS, 1 and 2
Druck
Active
Gas pressure (absolute)
Hydraulic pressure (gauge)
Gas pressure (gauge)
(At low current)
Specific values (continued)
+ 3 more
DynaGreen Environmental UK
Active
DIN EN 14791
IEC 60519-11
BS EN ISO 16911-1:2013 using
DIN EN 14792
DIN EN 13126-19
+ 3 more
BS EN ISO 16283-1:2014+A1:2017BS EN ISO
BS EN ISO 16283-2:2020
BS EN ISO 140-4:1998
ISO 1407
BS EN ISO 9972:2015
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and Appx. 3 of HSG 227 (2004))
in Appendix 5 of HSG 227 (2004)
guides HSG 264 (2012) and
(HSG 264, 2012)
ERC Testing
Active
DIN EN 1863-1
BS EN ISO 10077-1:2006
published 2024) for BS EN
DIN EN 1863-2
BS EN ISO 10077-2:2017
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Efectis UK/Ireland
Active
EN 1364-3
DIN EN 1366-4
EN 1364-4
BS 476-21
BS 476-22
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DIN EN 14791
IEC 60519-11
BS ISO 11338-1:2003
DIN EN 13284-1
DIN EN 14385
+ 3 more
(HSG 248) – 2021
(PCM) based on HSG 248
based on BS EN 12457
DIN EN 1948-4
dbSNP rs1800562, rs1799945, rs1800730, r
(HSG 264, 2012)
HSG 227 (2004))
(HSG 248) – 2021
(PCM) based on HSG 248
ISO 3651-2
ASTM A262 Methods A, C & E
ISO 7438
ASTM G28-2022 Method A
ASTM G48 Method A
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DIN EN 1303
DIN EN 12209
DIN EN 14846
BS 3621:2007+A2:2012
BS 8621:2007+A2:2012
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Enertek International
Active
DIN EN 12279
DIN EN 12278
-22018G/A, rs182549
DIN EN 303-2
DIN EN 15502-2-1
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Enquin Environmental
Active
(HSG 248) – 2021
(Section 2) based on HSG 248
(Section 4) based on HSG 248
staining based on HSG 248
(HSG 264, 2012)
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Enviraz Surveys
Active
HSG 264 (2012) and Appx. 3 of
(HSG 264, 2012)
HSG 227 (2004))
Appendix 5 of HSG 227 (2004))
Envirocare Midlands
Active
(HSG 248) – 2021
SOP/11, based on HSG 248
(PCM) based on HSG 248
(HSG 248) – 2021
DIN EN 12457-2
3.02 based on HSG 248
staining based on HSG 248.
(PCM) based on HSG 248
Environmental Compliance
Active
requirements of BS EN 15259:2007
DIN EN 14181
DIN EN 13126-19
DIN EN 15058
DIN EN 14789
+ 3 more
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