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
๐Ÿ‡ฉ๐Ÿ‡ช DIN EN ISO 3382-2 ๐Ÿ‡ฌ๐Ÿ‡ง BS EN ISO 3382-2 ๐Ÿ‡ซ๐Ÿ‡ท NF EN ISO 3382-2 ๐Ÿ‡ฎ๐Ÿ‡น UNI EN ISO 3382-2 ๐Ÿ‡ช๐Ÿ‡ธ UNE EN ISO 3382-2 ๐Ÿ‡ณ๐Ÿ‡ฑ NEN EN ISO 3382-2 ๐Ÿ‡ฉ๐Ÿ‡ช DIN EN ISO 1996-2 ๐Ÿ‡ฌ๐Ÿ‡ง BS EN ISO 1996-2 ๐Ÿ‡ซ๐Ÿ‡ท NF EN ISO 1996-2 ๐Ÿ‡ฎ๐Ÿ‡น UNI EN ISO 1996-2 ๐Ÿ‡ช๐Ÿ‡ธ UNE EN ISO 1996-2 ๐Ÿ‡ณ๐Ÿ‡ฑ NEN EN ISO 1996-2
1,670 Accredited labs
18 Countries

Showing 51โ€“75 of 349 labs

UKAS 0298 East Kilbride, GB
(HSG 264, 2012)
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UKAS 24642 Mansfield Woodhouse, GB
(HSG 264, 2012)
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UKAS 0472 Grays, GB
(HSG 248) โ€“ 2021 QOP03 based on HSG 248 (PCM) based on HSG 248 (PCM) based on HSG 248) QOP01 based on HSG 248 + 1 more
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UKAS 10792 Mansfield Woodhouse, GB
(HSG 248) โ€“ 2021 (PCM) based on HSG 248
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UKAS 6958 Witney, GB
(HSG 264, 2012) (HSG 248) โ€“ 2021
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UKAS 4234 Slough, GB
(HSG 248) โ€“ 2021 (PCM) based on HSG 248 (HSG 264, 2012)
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UKAS 4311 Elgin, GB
(HSG 264, 2012)
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UKAS 2544 Hebburn, GB
QOP03 based on HSG 248 QOP01 based on HSG 248 (HSG 248) โ€“ 2021 (PCM) based on HSG 248
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UKAS 30103 Nottingham, GB
(HSG 264, 2012)
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UKAS 0438 London, GB
(HSG 264, 2012)
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UKAS 30612 Cambridge Biomedical Campus, GB
DC CURRENT AC VOLTAGE (continued) AC CURRENT AC Voltage DIMENSIONAL + 3 more
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UKAS 4696 Rochford, GB
Analystsโ€™ Guide (HSG 248) (HSG 248) โ€“ 2021 Asbestos: The (PCM) based on HSG 248
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Attain RTC

Active
UKAS 27297 Tadcaster, GB
BS EN ISO 10140-2:2021 DIN EN 1366-4 BS EN ISO 10140-1:2021 Annexes BS EN ISO 10140-3:2021 EN 13823 + 3 more
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UKAS 0612 Orpington, GB
(HSG 248) โ€“ 2021 ) (PCM) based on HSG 248 Surveying) based on HSG 248
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UKAS 0389 Barrow-in-Furness, GB
Hydraulic pressure (gauge) TEMPERATURE DC Resistance BetriebsรผbertragungsmaรŸ Gas pressure (absolute) + 3 more
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BASEC Group

Active
UKAS 5950 Crownhill, GB
BS 4553-1:1998 BS 4553-2:1998 BS 4553-3:1998 BS 5308-1: 1986 (withdrawn) BS 5308-2: 1986 (withdrawn) + 3 more
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UKAS 7511 Brentwood, GB
(HSG 264, 2012) Appendix 5 of HSG 227 (2004))
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BDA Surveying

Active
UKAS 2791 Oadby, GB
(HSG 248) โ€“ 2021 (PCM) based on HSG 248
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BDA Surveying

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UKAS 0365 Oadby, GB
(HSG 264, 2012)
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UKAS 10646 Lincoln, GB
5 of HSG 227 (2004)) (HSG 264, 2012)
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UKAS 0578 Garston, GB
BS EN ISO 10140-2:2021 BS EN ISO 10140-3:2021 BS EN ISO 717-2:2020 ISO 7171 BS EN ISO140-3:1995 (withdrawn) + 3 more
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BSRIA

Active
UKAS 1053 Bracknell, GB
ISO 11451-1 IEC 62442-1 DIN EN 16147 DIN EN 12101-3 DIN EN 14825 + 3 more
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UKAS 0757 Dunfermline, GB
(HSG 248) โ€“ 2021 14B based on HSG 248 DIN EN 12021 14A based on HSG 248 (PCM) based on HSG 248 + 2 more
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UKAS 0726 Garretts Green, GB
(HSG 248) โ€“ 2021 ) (PCM) based on HSG 248) (PCM) based on HSG 248 staining based on HSG 248 (HSG 264, 2012)
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UKAS 1155 Halesowen, GB
staining based on HSG 248 (HSG 248) โ€“ 2021 (PCM) based on HSG 248 (HSG 264:2012)
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Industries

Audio and sound system design Public address and emergency systems Telecommunications and broadcasting Educational and institutional facilities Aviation and maritime communication

Related Standards

  • ISO 3382-2 Acoustics - Measurement of room acoustic parameters - Part 2: Reverberation time in ordinary rooms
  • ISO 1996-2 Acoustics - Description, measurement and assessment of environmental noise - Part 2: Determination of sound pressure levels
  • EN 60268-1 Sound system equipment - Part 1: General

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