noise – All about car

Noise cancellation is a pretty nifty science, even if it has been around for awhile. By projecting sound waves at an inverted frequency to those coming in, systems are able to decrease the overall noise heard. In a pair of noise-cancelling headphones, this means music untainted by the sounds of whatever noisy thing is nearby. In a car, it means a quiet cabin mostly free of the unwanted sounds coming from the engine and road. Hyundai Motor Group recently announced its new Road Active Noise Control (RANC), which improves on old tech (ANC) to reduce road noise by up to an additional 3dB, giving the Korean automaker an industry-best interior noise cancellation system. Old systems relied on insulation and dampers to passively kill sound, which ultimately resulted in extra weight and a faint, low-frequency buzz seeping through. The ANC system, on the other hand, uses software and components like controllers and microphones to measure and reduce noise. It’s like this: the mics pick up a sound, the software analyses it, and then the speakers spit out the inverse waves, thus cancelling it altogether. But that process was limited by the software, which struggled to get the cancellation done in the 0.009 seconds it takes for road or engine noise to reach the ears of passengers, says Hyundai. The new RANC will do the deed in just 0.002 seconds. “Using an acceleration sensor, RANC calculates the vibration from the road to the car and the control computer analyzes road noise,” the brand explains in a release. “As its computation and signal transfer speeds are optimized, it only takes 0.002 second to analyze the noise and produce an inverted soundwave, generated by the DSP (Digital Signal Processor).” “The microphone constantly monitors the road noise cancellation status, and sends the information to the DSP. RANC is able to conduct accurate noise analysis and rapid computation to combat road noise for the driver’s seat, the passenger seat and rear seats separately.”Hyundai anticipates the system working particularly well within the cabins of electric vehicles which, without combustion engines beneath them, will be particularly susceptible to road noise more than engine noise. The RANC system will debut in an unnamed upcoming Genesis
Origin: Hyundai’s Active Noise Control tech is a world-first

New rules coming into force today (1 July) dictate that all new fully electric vehicles must be fitted with an audible warning device to aid safety. In response to concerns that EVs pose a risk to pedestrians at low speed, the new ‘Regulation on the Sound Level of Motor Vehicles’ calls for silent vehicles to emit a sound when travelling at speeds under 12mph, or reversing. An acoustic vehicle alert system (AVAS) will generate a noise similar to that made by conventional combustion engines, and can be deactivated when judged necessary by the driver. The devices will be fitted to all new EVs with at least four wheels sold in the UK henceforth, and hybrid vehicles from July 2021 onwards. Roads minister Michael Ellis said: “The government wants the benefits of green transport to be felt by everyone, and understands the concerns of the visually impaired about the possible hazards posed by quiet electric vehicles. “This new requirement will give pedestrians added confidence when crossing the road.” A number of manufacturers, including Mitsubishi, Nissan and Toyota, already have some sort of AVAS fitted to their electric vehicles. Jaguar has equipped the I-Pace electric SUV with a system specifically tuned for the visually impaired, developed in conjunction with UK charity Guide Dogs for the Blind. The new law comes as part of a government drive to facilitate the mass roll-out of zero-emissions vehicles. The sale of new combustion-engined vehicles is set to be banned in the UK from 2040 onwards, although government advisors recently called for this to be brought forward to
Origin: All electric cars to have pedestrian warning noise