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Similar to technology found in noise-cancelling headphones, the system was developed by Israeli firm Silentium. Jaguar Land Rover is the first manufacturer to integrate the Active Acoustics software, which is now available for buyers.
The technology uses up to six strategically positioned accelerometers on a vehicle’s chassis to monitor unwanted road noise and send a signal to an on-board control unit with Silentium’s software. The system then plays an ‘anti-noise’ signal through the vehicle’s speakers, inverting the signal 180 degrees. The pressure waves from the exterior noise and the manufactured anti-noise reach occupants’ eardrums at exactly the same time, cancelling each other out.
The system removes 90% of unwanted noise across a broad band of frequencies, from 20Hz up to 1kHz. It results in a quieter vehicle, which Silentium said can prevent driver fatigue.
The company said the technology also offers vehicle manufacturers a way to reduce reliance on costly passive noise damping and insulation materials, and reduce vehicle weight – an increasingly important factor as the industry moves towards electric mobility.
“Active Acoustics will change the way car manufacturers reduce, cancel and enhance sound inside their vehicles, and how customers perceive and interact with these sounds,” said Anthony Manias, Silentium head of automotive.
It was initially unclear from a Silentium press release what effect – if any – the system would have on noise and vibrations from motorway rumble strips, which can alert drivers to lane boundaries or upcoming junctions, but a spokeswoman told Professional Engineering: “The Active Road Noise Cancellation (ARNC) system measures a combination of different noise sources from outside the car. The software is programmed to distinguish between ‘unwanted’ noise, such as continuous rumbles from the tyres and road, and the ‘wanted’ noise, including louder and more abrupt rumble strips, police sirens or car horns. The wanted noises are separated in the audio and so are not reduced by the ARNC.”
Hyundai and Samsung subsidiary Harman International introduced a similar technology, based on Harman's Halosonic technology, in February this year. The Road-Noise Active Noise Control (Ranc) system reduces noise by up to 50%, and was first featured in the Genesis GV80 SUV.
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.