How Noise Canceling Tech Works in Cars
Modern technology can make for calmer cabins.
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QuickTakes:
If you're a frequent flier, you may have experienced the joy of headphones with active noise cancellation. Once enabled, they can remove the droning hum of a noisy airplane cabin and turn it into a more quiet, serene place. This same technology can work for your car, too.
Active Noise Cancellation Technology Explained
Noise cancellation is a step beyond the passive sound-deadening material that many manufacturers apply to the inside of their cars. Whether it's heavy rubber or specially engineered foam, these materials are designed to soak up sound and prevent unwanted noise from getting into the cabin so you can focus on what you'd like to hear. Insulation materials like this can be quite effective, but they add weight. When it comes to efficiency, lightness is crucial.
Active noise cancellation (ANC), also known as active noise control or active noise reduction, is much more advanced. To understand how it works, you have to understand how sound works. Any noise you hear is a pressure wave — minute compressions that resonate through the air away from their source.
To neutralize sound, you create opposing waves, or so-called anti-phase sounds. If a wave of positive pressure hits an equal wave of negative pressure, there is total silence. That's how ANC works. A microphone listens for some unwanted sound, then runs it through a processor to digitally invert it. That inverted sound is then played through the speakers, neutralizing the unwanted incoming noise.
How It Works in Vehicles
Neutralizing noise is relatively easy on a plane because the biggest noise is the continual drone from the engines, which rarely changes. This is why noise-canceling headphones can do a great job at blocking that constant hum, but they don't always do so great at muting the screaming baby.
In a car, the most annoying sounds are similar in character. The droning of tires on asphalt, for example, generally stays at a similar pitch and thus is easily countered. Engine noise is a little more tricky as it changes based on the speed at which the engine is turning. However, by allowing an ANC system within the car to interface with the car's main computer, it can modulate the inverse sound waves and effectively keep up as the car increases speed.
Cars make a great platform for this because they already have comprehensive sound systems — speakers throughout the cabin that can play the anti-phase sounds. The only added cost would be a few microphones to detect troubling noise and the processors required to generate the anti-phase sounds. Such systems are generally not intended to be disabled by drivers, though some aftermarket solutions exist for drivers who might add audio equipment not compatible with active noise cancellation.
Cars with active noise cancellation
Car noise cancellation may seem a little like science fiction, but it's increasingly commonplace. On the high end, luxury cars such as the Lexus LS, Lincoln Aviator, and Mercedes-Maybach S-Class can be equipped with ANC. Even Honda and Nissan offer the technology in their lineup. In 2023, the technology made its way to the Chevrolet Colorado midsize pickup as well.
