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
Researchers 'count cars' -- literally -- to find a better way to control heavy traffic
10.08.2017 | Florida Atlantic University
From parking garage to smart multi-purpose garage
19.07.2017 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
17.08.2017 | Physics and Astronomy
17.08.2017 | Earth Sciences
17.08.2017 | Physics and Astronomy