Hyundai Motor Group says it has developed a world-first Road Noise Active Noise Control (RANC) system. The new system dramatically reduces noise within the cabin of a vehicle.
RANC builds on the company’s current Active Noise Control (ANC) technology, which actively reduces noise by emitting sound waves inverted to incoming noise. ANC analyses the in-cabin sound to decrease engine and road noise, as opposed to the passive method of blocking noise through sound insulation.
Existing insulation methods involved insulation materials and dynamic dampers which increased weight and failed to block all buzzing infrasound. In contrast, ANC utilises much lighter parts like microphones and controllers to control the noise and reduces infrasound more efficiently.
Current ANC technology is limited by noise measurement and analysis technology, which is only able to be utilised when the noise is constant and the occurrence of the noise predictable. The new RANC can significantly improve quietness within the cabin by analysing various types of noise in real-time and produce inverted sound waves. It can process different types of road noises such as resonant sounds created between tyres and wheels or rumble sounds coming up from the road.
RANC uses an acceleration sensor to calculate the vibration from the road to the car, with the control computer taking 0.002 seconds to analyse the road noise and produce an inverted sound wave. The microphone constantly monitors the road noise cancellation status and sends the information to the digital signal processor (DSP).
Hyundai Motor Group said RANC was able to reduce in-cabin noise by 3dB – roughly half the noise compared to without RANC – potentially decreasing the amount of unsprung weight in a vehicle and utilising fewer sound-insulating parts and dampers.
The conglomerate has completed Korean and American patent applications for the location of sensors and the signal selection method – core RANC technologies. It added that RANC will first appear in an upcoming Genesis model.