In a 2015 dining trends survey by Zagat, the number-two complaint by restaurant-goers, after service issues, was excessive ambient noise. People often have to speak excessively loud to be understood by their dining companions...

The term ‘speech privacy’ refers to how well a conversation is overheard and understood by an unintended listener. The need to prevent sound from intruding into adjacent spaces in both closed and open-plan settings...