With technological advances, modern internal combustion engines, electric and hybrid engines, vehicles have become very quiet. Now, tire noise is the new challenge for acoustic engineers. To neutralize it, they focus on integrating active noise reduction in cars.
Unlike passive noise reduction, which isolates surrounding sounds with soundproofing materials, active noise cancelling uses microphones to reduce or eliminate background noise. But how exactly does it work? What are the advantages of this technology in cars?
What is car noise cancelling?
Known to music lovers, active noise cancelling, also known as ANC, is present in many contemporary headphones. The latter are appreciated by users who want to enjoy their playlists without hearing ambient noise in public transport or open space offices, for example.
In cars, this technology aims to improve the driving comfort of motorists. As with headphones, active noise cancelling in cars works with strategically placed built-in microphones. Their mission is to capture ambient noise. Once detected, they are transmitted to a software that analyzes and sends a sound signal to the speakers. These diffuse an opposite sound wave, also called “phase opposition”, to cancel the original sound.
The significant reduction of road noise and vibrations improves driving comfort, reduces fatigue and stress, and of course, provides the best conditions for listening to music in the car.
The development of noise reduction in cars
Bose QuietComfort RNC (Road Noise Control) technology, Silentium’s Active Acoustics and Harman Kardon’s Halosonic are among the first advances in car noise reduction. The algorithms required to effectively remove noise are very complex. In addition to microphones, these systems include acceleration sensors that detect noise-generating vibrations. The anti-noise system operates throughout the cabin to allow the driver, as well as front and rear passengers, to enjoy the benefits of this technology.
In the future, Bose even wants to allow travelers to create a sound bubble according to the zones of the cabin to enjoy a personalized experience. Integrated in each seat, the speakers could then broadcast different content for each passenger or adjust the listening volume separately. It’s a great way to make calls without disturbing other passengers, to enjoy your music or to rest!
Also read: Why integrate speakers in headrests?
Safe driving with active noise cancelling
It is important to note that these technologies are designed to ensure the safety of road users. Just like when you run in an urban environment with noise-cancelling headphones or earphones, overly insulating acoustics while driving can be dangerous. (Also read: Transparency mode: just as important as ANC?)
Indeed, it is essential to remain aware of certain sounds such as horns and sirens. Note that active noise cancelling is most effective with low frequencies, while warning and hazard signals typically emit mid to high frequencies. This ensures that important sounds remain audible to the driver.
The benefits of car noise cancelling
Active noise control systems have several advantages. Their main objective is to improve the driving comfort of road users by reducing noise pollution, which promotes better concentration and calmer driving.
But these devices could also allow car manufacturers to reduce the weight of vehicles by replacing bulky insulating materials with these anti-noise systems. This configuration would reduce fuel consumption, CO2 emissions and vehicle manufacturing costs.
The technologies developed by Harman Kardon and Silentium are already available to car manufacturers. Active noise cancellation can be found in the latest Range Rovers, Range Rover Sport, Jaguars and Bentleys.