The yoga instructor spoke in a hushed, breathy tone designed to guide students into deep relaxation. The studio's ceiling-mounted speakers and clip-on mic were intended to carry her whispered cues to every mat. Instead, they carried a 4.1 kHz squeal that jolted 30 people out of savasana like a fire alarm for the nervous system.

The instructor lowered her voice further — the universal instinct when a mic misbehaves — which required more gain, which brought the system closer to feedback. She moved away from the speaker. The ring stopped. She moved back to demonstrate a pose. It returned. For 60 minutes, the class alternated between peaceful silence and sudden electronic shrieks, which the instructor gamely incorporated into the flow as "moments of acoustic awareness."

The studio had been treated with fabric panels for reverb control, which was good. But the ceiling speakers' coverage pattern overlapped directly with the clip-on mic's pickup, and the room's low ambient noise meant even tiny amounts of regeneration were audible. In a yoga studio running at 35 dBA background noise, feedback that would be masked in a conference room is painfully exposed.

The Moral: Quiet rooms expose feedback that louder rooms hide. Use SonaVyx Problem Detection during setup to find the feedback threshold in your actual noise environment — not just the one you assume.