Sound Transmission Class (STC)

Sound Transmission Class (STC) measures how well a sealed wall reduces airborne sound under controlled lab conditions. While useful for traditional construction, it does not reflect real-world performance in open or ventilated environments, where factors like gaps and airflow impact sound isolation.

Why STC Falls Short in Real-World Acoustic Environments

STC is often treated as a universal measure of acoustic performance, but its limitations become clear outside of controlled lab conditions. STC ratings are based on sealed wall assemblies with no gaps, airflow, or external variables, which makes them useful for comparing traditional construction materials. However, most modern work environments are far from sealed. Open-plan offices, shared spaces, and modular setups introduce variables like ventilation openings, door seals, and surrounding noise that significantly impact how sound behaves. This is where STC begins to lose relevance.

In practical terms, what people care about is not how much sound is blocked in a lab, but whether conversations remain private and distractions are reduced. Ventilated, furniture-based systems are designed for real use, which means balancing airflow, comfort, and acoustic control. Because of this, their performance is better understood through speech reduction, which reflects how much intelligible conversation is actually diminished in a given space. This approach aligns more closely with real-world expectations, focusing on privacy and usability rather than idealized conditions that rarely exist outside of testing environments.

Related Terms

• Speech Privacy
• Speech Reduction
• Noise Flanking

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