Sensors and loudspeakers reduce in-car racket.
Road block: anti-sound could stop drivers getting hoarse.
Tired of shouting to your passenger as you drive, striving to make your voice heard over the rumble of the car? Help is on the way, in the form of strategically placed sensors and loudspeakers.
Researchers at the Korea Advanced Institute of Science and Technology (KAIST) in Taejon have developed a prototype system that shaves up to 6 decibels off the typical motoring noise of around 60 decibels. Thats more than any other comparable method1.
Road booming noise - the din inside a car created by vibrations in the wheels that are transmitted through the suspension - is particularly difficult to eliminate. It depends on speed, road surface and suspension, among other factors. It is thus more variable than the steady drone of aircraft or machinery.
As a result, there is no single ideal location for vibration transducers in all vehicles. And the computational demands of converting the transducer signal into an anti-sound output at the loudspeakers means that active-control systems struggle to respond fast enough to changing noise levels.
Nevertheless, Shi-Hwan Oh and colleagues at KAIST have come up with a relatively simple system that gives a fair reduction in noise.
In principle, the best way to measure motoring noise vibration would be to cover the vehicle with transducers. But if there are too many, it is impossible to combine all their inputs into an anti-sound response. A good compromise, the researchers find, is four transducers attached to the left and right front suspension system.
Similar tests helped them to locate the best positions for the loudspeakers: on the floor behind the two front seats. This creates sweet spots of noise reduction around the heads of the driver and front passenger.
Ohs team also designed an algorithm that converts the transducer signals quickly and efficiently into a loudspeaker output signal. To reduce noise elsewhere in the car, more transducers and speakers would be needed, which would increase the complexity of the computations.
PHILIP BALL | © Nature News Service
Study sets new distance record for medical drone transport
13.09.2017 | Johns Hopkins Medicine
Researchers 'count cars' -- literally -- to find a better way to control heavy traffic
10.08.2017 | Florida Atlantic University
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
16.03.2018 | Earth Sciences
16.03.2018 | Physics and Astronomy
16.03.2018 | Life Sciences