In many restaurants there is something called ''the cocktail party effect''. This effect causes people to raise their voices to make themselves understood. The result is that the people at the next tabel will do the same thing and as a result people will start shouting at each other.
The cocktail party effect significantly increases the sound level in the room. This can be solved by improving the acoustics. This should preferably be done as close to the customers as possible, for example by applying acoustic solutions directly above the tables. Sound is then dampened as much as possible at the source and spreads less quickly in the room.