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
🇩🇪 DIN EN ISO 3382-2 🇬🇧 BS EN ISO 3382-2 🇫🇷 NF EN ISO 3382-2 🇮🇹 UNI EN ISO 3382-2 🇪🇸 UNE EN ISO 3382-2 🇳🇱 NEN EN ISO 3382-2 🇩🇪 DIN EN ISO 1996-2 🇬🇧 BS EN ISO 1996-2 🇫🇷 NF EN ISO 1996-2 🇮🇹 UNI EN ISO 1996-2 🇪🇸 UNE EN ISO 1996-2 🇳🇱 NEN EN ISO 1996-2
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ACCREDIA 01454 Vallefoglia, IT
DIN EN 16825 ISO 22041 EN ISO 22043 DIN EN 13771-1 DIN EN 14511-2 + 3 more
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ACCREDIA 02089 Fino Mornasco, IT
ETSI EN 301 489-6 DIN EN 61326-2-6 IEC 61326-3-1 IEC 61326-3-2 IEC 60669-2-5 + 3 more
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DIN EN 12457-2 DIN EN ISO 6888-1 DIN EN 15634-1 ASTM D888-18 EPA 8015 + 3 more
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DIN EN 1097-7 DIN EN 1097-6 DIN EN 933-10 DIN EN 933-8 DIN EN 1427 + 3 more
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ACCREDIA 01160 Assemini, IT
EPA 8015 EPA 3511 2014 EPA 8260 EPA 6020 BS EN ISO 17294-2 + 3 more
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ACCREDIA 01827 Roma, IT
ETSI EN 319 412 ETSI EN 319 401 ETSI EN 319 411-2 ETSI EN 319 411-1
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ACCREDIA 01376 Putignano, IT
DIN EN 12457-2 EPA 3545 DIN EN ISO 14402 UNI 10802 EPA 1613 + 3 more
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ACCREDIA 00473 Stazzano, IT
ISO 17604 DIN EN 12457-2 DIN EN ISO 6888-1 ISO 19250 EPA 3630 + 3 more
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ACCREDIA 00627 Busto Arsizio, IT
ASTM E 415 21 DIN EN 15266 ASTM D 1329 UNI EN ISO 22391 DIN EN ISO 10140-1 + 3 more
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ACCREDIA 00173 Brugine, IT
ETSI EN 301 489-1: V2.2.3 IEC 62109-1 DIN EN 50178: 1998 IEC 61000-4-16: 2015 IEC 62109-2 + 3 more
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ACCREDIA 00321 Pogliano Milanese, IT
IEC 60335-2-51 DIN EN 60068-2-30 IEC 61000-6-1 IEC 60335-2-54: 2008 DIN EN 50564 + 3 more
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ACCREDIA 00754 Verbania, IT
ISO 37 &10 based on HSG 248 BS EN ISO 6509-1:2014 ISO 815-1 ISO 815-2 + 3 more
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Telsy

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ACCREDIA 01747 Orvieto, IT
ETSI EN 319 412 ETSI EN 319 401 ETSI EN 319 411-2 ETSI EN 319 411-1
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ACCREDIA 00999 Carugate, IT
DIN EN 60068-2-30 IEC 61000-6-1 AS/NZS CISPR 22:2006 IEC 61000-6-2: 2005 ETSI EN 303 446-2 + 3 more
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WTLAB

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ACCREDIA 01077 Tribano, IT
IEC 62109-1 IEC 61400-21-1 IEC 62109-2 DIN EN 60598-2-4 DIN EN 60068-2-30 + 3 more
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ACCREDIA 00165 Roncoferraro, IT
ISO 13720 DIN 3388-4 EPA 6020 EPA 3535 DIN EN ISO 6888-1 + 3 more
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Z LAB Srl

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ACCREDIA 01046 Cerea, IT
DIN EN ISO 11546-1 UNI EN ISO 9295 DIN EN ISO 11957 ISO 354 ISO 3741 + 3 more
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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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