In various Audi models, the Audi voice control system can be used to operate the most important navigation, radio and hands-free car phone functions by speaking the necessary commands directly. The Audi A8 makes all the functions of the navigation system available by voice control. The driver or front passenger can use this method to enter roads, house numbers and special destinations and can control the route calculation and route selection processes. To make a speech input, the driver presses the “Push to Talk” (PTT) button on the multifunction leather-covered steering wheel. The system can accept various accents and dialects, and even identifies words spoken quickly and run together. There is an electronic background noise reduction circuit to filter out unwanted noise effectively.