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 reduction Represents how well the headphone reduces ambient noise when the active noise cancellation feature is activated. Sensitivity An assessment of how loud wire connected headphones will play for a given audio input signal level. This is an important consideration if the headphones will be used with audio devices that have relatively low maximum audio output signal levels like some battery powered portables.