[duped]

Honestly the cheapest way to muffle sound is to not create it in the first place. Guests make noise to hear themselves over other guests and the din of the room, the quieter the room, the quieter the guests, etc.

Essentially, the louder the noise floor, the louder the signal has to get to be intelligible at every table, which raises the noise floor, creating a feedback loop. Good acoustic design in a space accounts for this by minimizing how much acoustic energy is present in the room - both by removing it (with acoustic treatment), spreading it away from sources (by isolating tables/booths, using hard surfaces to reflect sound away, etc), and preventing it from being created in the first place. For example, keeping bus stations behind galley doors and training staff not to clink silverware/glasses/dishes when filling bus bins and avoid playing loud music, etc.

In my experience, most restaurants fail at this because all the people who do it well are in the high-end restaurant business, which most restaurants are not. If the key to a space that isn't too loud is to limit the number of patrons, have dining room space allocated to treatment between tables, have highly trained staff with consistent management, and a big enough kitchen space with heavy enough doors to isolate the sound within - your only option is to be a high end restaurant.

But the high end places fail at it because they don't care and want to maximize the guest throughput because their margins still suck.

[chefandy]

High-end places not only still have bad margins, they're quite often worse!

Low-end places are often even more carefully designed, though, but they're designed for different things: high turnover and low staff wages, meaning simple, flat, easy-to-clean (and sanitize), nearly-zero-maintenance surfaces like bare laminated tabletops and quarry tiles. Especially once you start moving into fast casual, they want their diners comfortable enough to enjoy their meal, but not comfortable enough to linger, which is often a tough balance to strike.

The look of high-end places is like putting your sales people in nice suits. I don't think most places are trying to maximize throughput-- if they're not completely booked at least a few nights per week they're probably not staying open-- I think they're trying to maximize check averages. Nothing inspires "maybe I'll get the dry aged wagyu app and flip to the expensive page in the wine list tonight" thoughts like a luxe dining room.