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.
Noise cancelling headphones often have their own microphone, recording the outside atmosphere and creating a sound wave that actively cancels it out. Passive noise reduction headphones merely create a seal around or in your ears that keeps out noise. As for which is best, it usually depends on your situation: 1  In general, the higher the price tier, the higher the quality. 2  Passive noise reduction works well with music. 3  Quality is very much subjective.