The restaurant was gorgeous. Exposed brick walls, polished concrete floor, pressed tin ceiling, floor-to-ceiling windows. The designer had won a local award. The Yelp reviews all said the same thing: "Amazing food. Beautiful space. Could not hear a single word anyone said."

Every surface in the room was acoustically reflective. The RT60 measured 2.5 seconds — appropriate for a small concert hall, catastrophic for a space where people needed to communicate across a 60-centimeter table. Speech intelligibility was approximately STI 0.35, which meant diners understood maybe half the words their companions said and none of what the server said.

The Lombard effect took over. As ambient noise from reflections built up, people spoke louder to be heard, which created more noise, which made them speak louder still. By 8 PM on a Saturday, the sound level reached 88 dBA — louder than a busy highway. Servers resorted to pointing at menu items. Couples on first dates stared at each other in conversational defeat.

The owner eventually hired an acoustician who installed fabric-wrapped panels on 30% of the ceiling and added upholstered banquette seating. RT60 dropped to 0.8 seconds. The noise level fell by 12 dB. Yelp reviews changed overnight.

The Moral: Restaurants need RT60 below 1.0 seconds for comfortable conversation. Measure with SonaVyx RT60 before opening — acoustic treatment is far cheaper than losing customers.