Articles tagged “sti”
19 articles covering sti in acoustic engineering and building design.
Mosque Acoustics Design Guide — RT60, STI, and the Dome Problem
A complete guide to mosque acoustic design. Solve dome focusing, marble reflections, and PA system conflicts. With worked calculations per ISO 3382.
Why Your Church Has Terrible Speech Intelligibility — And What STI Actually Measures
The average historic UK church has RT60 of 3.5–5.0s. The human voice requires STI ≥ 0.45 to be understood. At RT60 > 2.5s, STI drops below 0.45 without a PA system. Here is the physics and the fix.
How to Pass WELL v2 Feature 74 Acoustics First Time — The 8-Step Process
73% of WELL F74 acoustic assessments fail Part 3 on first submission. This 8-step process prevents every common failure mode before assessment — from early-stage RT60 design through post-construction STI verification.
How to Read an Acoustic Report — What Every Architect Needs to Understand
Acoustic reports contain RT60 tables, octave band plots, compliance matrices, and STI data. Here is how to read each section, what the numbers mean, what 'pass' and 'fail' look like, and what to challenge if you disagree.
Can Everyone Hear Your Calls? Why Open Office Speech Privacy Fails
If you can clearly understand a colleague's phone conversation from 4 metres away, your office STI is above 0.50 — and your speech privacy is non-existent. WELL v2 Feature 74 Part 3 requires STI < 0.50. Here is how to achieve it.
Speech Privacy Index (SPI): How to Measure and Achieve Acoustic Privacy
A technical guide to the Speech Privacy Index (SPI) per ASTM E1130: how it relates to STI and AI, the three elements that determine privacy, privacy classification thresholds, and practical design strategies for offices, healthcare, and open plan environments.
Why Your WELL Acoustic Certification Will Fail: The 5 Errors Most Architects Make
Five calculation errors that cause WELL v2 Feature 74 acoustic certifications to fail at assessment stage — each with the specific number that trips the design. Passing RT60 is necessary but not sufficient. Here is what WELL assessors actually check.
WELL AP Exam: Acoustic Questions Study Guide — Every Feature 74 Detail You Need to Know
Comprehensive study guide for WELL AP exam acoustic questions covering Feature 74 (Sound) Parts 1-3, RT60 thresholds, background noise criteria, STI calculations, and speech privacy requirements. Includes practice questions with explained answers.
Free WELL v2 Feature 74 Acoustic Calculator — Generate Your Compliance Report
Calculate WELL v2 Feature 74 acoustic compliance free. Parts 1, 2, and 3. RT60, background noise, and speech privacy (STI) checked simultaneously. Generate a WELL F74 compliance report in PDF format.
What Is STI (Speech Transmission Index) — Can People Actually Understand Speech in Your Room?
STI measures how much a room degrades speech from source to listener, on a scale from 0 (unintelligible) to 1 (perfect). An STI below 0.50 means one in four words is lost. Here is how STI works, what scores you need, and why reverberation time alone is not enough.
ODEON Alternative: Free Room Acoustics Software for RT60, STI, and Compliance
ODEON is the gold standard for ray tracing room acoustics, but its €5,000+ license and steep learning curve put it out of reach for many professionals. This comparison examines where ODEON excels, where a free cloud-based alternative like AcousPlan covers 80% of use cases, and how to decide which tool fits your project.
Open Plan vs Enclosed Offices: The Acoustic Trade-offs That Determine Workplace Satisfaction
Open plan offices cost 40-60% less per desk but generate 3x more acoustic complaints. Enclosed offices provide speech privacy but reduce collaboration. Here is the acoustic comparison with STI measurements, distraction distance data, WELL compliance pathways, and the hybrid compromise that works.
WELL v2 Feature 74 vs LEED v4.1 EQ Acoustic Performance — Which Is Stricter?
WELL v2 Feature 74 and LEED v4.1 EQ both award acoustic performance credits — but they measure different things. WELL is stricter on speech privacy (STI). LEED is stricter on HVAC noise (NC-35 vs WELL's 45 dBA). Full clause-by-clause comparison.
ANSI/ASA S12.60 Complete Guide: American Classroom Acoustics Standard
ANSI S12.60-2010 is the American standard for classroom acoustics, specifying maximum RT60 (0.6s), maximum background noise (35 dBA), and minimum STI (0.60). Here is every requirement explained with calculation examples, compliance methods, and how it compares to BB93 and DIN 18041.
IEC 60268-16 Complete Guide: Speech Transmission Index (STI) Standard
IEC 60268-16:2020 defines the Speech Transmission Index — the definitive metric for speech intelligibility in rooms. Here is every aspect of the standard explained: the STI calculation method, STIPA measurement procedure, quality scale, and how building codes worldwide use it.
WELL v2 Feature 74 (Sound) Complete Guide: Every Requirement, Threshold, and Compliance Path
WELL v2 Feature 74 has three parts: Sound Mapping (RT60), Sound Barriers (background noise), and Sound Masking (speech privacy/STI). Here is every threshold, every space type, every measurement condition, and the compliance pathway for each part — from precondition to optimization.
Open Plan Office Acoustic Design: The Complete Guide (WELL v2 | BS 8233 | ISO 3382)
The definitive guide to open plan office acoustics covering WELL v2 Sound features, BS 8233 targets, ISO 3382-3 open plan parameters, sound masking, and the ABC rule. Includes worked examples, compliance checklists, and cost analysis for 200-2000m² floor plates.
The School Nobody Could Learn In: What ANSI S12.60 Failures Cost Students
35% of UK classrooms fail BS 8233 acoustic targets. The reason is not RT60 — it is STI. Architects design for reverberation time and ignore the speech transmission index calculation that ANSI S12.60 and DIN 18041 actually require. This is what that costs.
WELL v2 Feature 74 Decoded: Every Acoustic Requirement, Every Calculation, Every Clause
WELL Building Standard v2 Feature 74 has three parts with different requirements for RT60, background noise, and speech privacy. Most WELL assessors fail Part 3 because the speech privacy STI calculation is never written down in one place — until now.