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.
How Noise-canceling Headphones Work. Bose was the first company to introduce noise-canceling headphones. See more pictures of essential gadgets. One man's noise is another man's music, but no matter what your taste, ambient noise is the enemy. Luckily, there's a piece of audio equipment designed especially to maximize your listening experience, keeping ambient noise out without sacrificing your music's sound quality.