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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Jordan Design and Development Bureau

UKAS 4515 Amman 11190, JO

MIL-PRF-46103E DIN EN ISO 15106-3 DIN EN ISO 1522 DIN EN ISO 1523 ISO 16935:2007 + 3 more

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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