An information processing system for use in a vehicle includes a main body for various operations and a portable device in data communication with the main body. The portable device is installed in front of a seat, and has a speaker system for outputting an audible signal. A virtually created source of the audible signal whose location or direction relative to the driver and other occupants of the vehicle is identified by the information processing system. A sound field localization based on a data processing for the audible signal makes the sound signal heard from the identified direction. Perception of the audible signal from the virtually created source of the audible signal facilitates awareness of a surrounding environment of the vehicle.