 The same loudspeakers may also be used to minimize road and engine noise with active noise control, or they may be used to augment engine sounds, for instance making a smaller engine sound bigger.In 1904, well before commercially viable technology for mobile radio was in place, American inventor and self-described "Father of Radio" Lee de Forest did some demonstration around a car radio at the 1904 Louisiana Purchase Exposition in St. Louis.Around 1920, vacuum tube technology had matured to the point where the availability of radio receivers made radio broadcasting viable.