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
🇪🇸
UNE EN ISO 1996-2
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NEN EN ISO 1996-2
1,670
Accredited labs
18
Countries
Showing 101–125 of 1,670 labs
Absolute Calibration
Active
DC Resistance
CFH-Gen, Macula-Degeneration
DC RESISTANCE (continued)
DC VOLTAGE
DC VOLTAGE (continued)
+ 3 more
Acorn Analytical Services
Active
(HSG 248) – 2021
(PCM) based on HSG 248
staining based on HSG 248
(HSG 264, 2012)
Appendix 5 of HSG 227
Acoustic Design Technology
Active
ISO 7171
BS EN ISO 140-4:1998
HTM 08-01
ISO 1407
BS EN ISO 717-2:2020
ISO 11654
BS EN ISO 10140-2:2021
ISO 7171
ISO 354
BS EN ISO 10140-3:2021
+ 3 more
Sound Calibrators
Pistonphones
based:
level
Microphones
+ 2 more
DIN EN ISO 11127-6
DIN EN 13727
1) BS EN ISO 11930:2019+
2) QMIC WI 22, based on BS EN
Taupunkttemperatur
Railway braking — urban guided transport
Temperaturtransmitter
Widerstandssensor *)
–30 °C
+ 3 more
Air Surveys
Active
(HSG 248) – 2021
APP 7 based on HSG 248
(PCM) based on HSG 248
(PCM) based on HSG 248)
APP 15 based on HSG 248
+ 2 more
BS EN ISO 16283-1:2014+A1:2017BS EN ISO
BS EN ISO 140-4:1998
ISO 1407
ISO 7171
BS EN ISO 9972:2015
+ 1 more
(HSG 248) – 2021
AEC 1 based on HSG 248
(PCM) based on HSG 248
AEC 6 based on HSG 248
Airbus Defence and Space
Active
- Gleichspannung
/ Messgeräte
1 µV
Quellen
> 1 V
+ 3 more
Airtech Analysis
Active
(HSG 248) – 2021
(PCM) based on HSG 248
staining based on HSG 248
(HSG 264, 2012)
Appendix 5 of HSG 227 (2004))
ISO 23351-1
ASTM E 1354
DIN EN ISO 717-1
DIN EN ISO 717-2
DIN EN ISO 3382-1
+ 3 more
BS ISO 18283:2022
ASTM D2234 (location E)
ASTM D2013 (location B)
BS ISO 5074:2015; and
ASTM D409:2016
+ 3 more
Alkali Environmental
Active
BS EN ISO 16911-1:2013 using
DIN EN 14181
DIN EN 13126-19
DIN EN 15058
DIN EN 14789
+ 3 more
Allgäuer Messzentrum
Active
Durchmesser 1 mm
510 mm
Rundheitsabweichung 1 mm
Parallelitätsabweichung
Rundheitsabweichung
+ 3 more
Allied Aerosystems
Active
DC Resistance
2.92 mm systems (continued)
DC VOLTAGE
AC CURRENT
DC Power
+ 3 more
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