Principal Nakamura had given 200 assemblies in her career. She could command a room of 800 teenagers with a single raised eyebrow. But the moment she stepped into the new gymnasium and opened her mouth, physics won.

The gym was an acoustic horror show: poured concrete floor, painted cinder-block walls running perfectly parallel for 30 meters, and a steel deck ceiling. Every sound bounced between those walls like a pinball, gaining energy with each reflection. The portable PA on its tripod stand might as well have been a feedback cannon aimed directly at itself.

She tapped the mic. A squeal erupted. The AV kid yanked the gain down. She tried again, quieter. Nobody past row five could hear her. She leaned in closer. The squeal returned, this time at a different frequency — the room had multiple resonant modes ready to ring. The assembly devolved into a game of acoustic whack-a-mole while 800 students filmed on their phones.

Parallel hard walls create flutter echo and dramatically reduce gain-before-feedback. The room's RT60 was well over 3 seconds, meaning the PA was fighting its own reflections. Without measurement, no amount of EQ guesswork would tame it.

The Moral: Measure first, EQ second. SonaVyx Problem Detection maps every feedback-prone frequency in seconds, so you can notch them surgically instead of fighting blind.