This has to do with the drivetrain of the car. In simpler terms, the power delivery system of the car. A 2wd or a two wheel drive is any general stick shift(manual transmission) car you drive. Either the front two rotates and pull your car or the back two rotates and push your car forward. For a 4wd or a four wheel drive, you can switch to all of the wheels being driven. Provides better grip on the road.
How the system works. Active Noise Cancellation (ANC) is designed to dramatically reduce low frequency noise in the interior. The system operates whenever the car is running, regardless of whether the audio system is on or off. There are two microphones in the cabin area.
What is interference signal? Answer Wiki. There are two types of interference: radio frequency interference (RFI), and electrical interference. RFI is caused by radio and TV transmitters, communications equipment, cable television systems and other types of equipment that generate radio frequency energy as part of their operation.