A driver or passenger could have a private phone call as well. Calls on speaker are usually heard by all people in the car. With the system, passengers can enjoy individual choices of music while retaining the ability to converse among themselves, which isn’t possible if they are enjoying private music with earphones. Sounds that are necessary to the driver but that are disturbing to other passengers can be controlled too, such as audible directions from the navigation system or warning sounds from the driving assistance system. Music or direction guides that a driver is listening to won’t be heard by a sleeping child in the back seat. Hyundai Motor said it started developing the system in 2014 and is almost ready to install it in mass-produced cars. “This sound system will become necessary as the autonomous driving era nears and demands for entertainment inside a car evolve,” said Ih Kang-duck, a researcher in charge of developing the system.