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
1,868 Accredited labs
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TERANA NIEVRE

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COFRAC 1-6949 Nevers Cedex, FR
DIN EN ISO 17294-2 NF T 90-412 DIN EN ISO 10304-1 NF X 31-615 ISO 5815-1 + 3 more
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TERANA PUY-DE-DOME

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COFRAC 1-6120 Lempdes, FR
NF T 90-412 NF U47-101 DIN EN ISO 7899-1 DIN ISO 16649-2 DIN EN ISO 6888-2 + 3 more
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TOXILABO

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COFRAC 1-1941 Nantes, FR
NF ISO 21438-3 NF X 43-264 NF ISO 21438-1 ISO 16200-2 NF ISO 21438-2 + 3 more
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VALEO ELECTRIFICATION - Laboratoire d'essais et de validations

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COFRAC 1-6561 Sainte-Florine, FR
ISO 16750-3 IEC 60068-2-80) IEC 60068-2-53 limitée à : IEC 60068-2-14 fait IEC 60068-2-1 et + 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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