Budget cuts merged two classes into the gymnasium. Mrs. Chen, a 20-year teaching veteran, was reassured it would be "temporary." She walked into a room with a 10-meter ceiling, hardwood floor, painted block walls, and 60 students who were already excited about not being in a normal classroom.

She began her lesson. Her voice left her mouth, hit the back wall 15 meters away, bounced to the ceiling, came down to the floor, and returned as a smeared echo that arrived on top of her next sentence. Every word she said interfered with the word before it. Students past row three couldn't distinguish between "mitosis" and "my toeses" — both of which sounded approximately like "mmmoooosss."

The RT60 was 3.0 seconds. For speech intelligibility, classrooms need RT60 below 0.6 seconds. Mrs. Chen was operating at five times the acceptable limit. The Speech Transmission Index was approximately 0.25 — classified as "bad" by IEC 60268-16, meaning less than 40% of words could be understood. She resorted to writing everything on the board while students read silently, which was education by surrender.

Gymnasiums are designed for physical activity, not speech. Hard surfaces maximize durability and cleaning ease at the total expense of acoustic comfort.

The Moral: Repurposing a space for speech requires measuring it first. SonaVyx RT60 quantifies exactly how bad it is — and how much treatment is needed to make it usable.