A team of researchers has discovered an acoustic technique to make objects invisible using sound waves. Their system of acoustic relays could potentially be used to hide large objects like submarines.
This content was published on
2 minutes
EPFL/sb
The scientists from Lausanne’s Federal Institute of Technology (EPFL), in association with the Technical University of Vienna and the University of Crete, devised a system of acoustic relays placed at strategic locations that enabled sound waves to propagate at constant amplitude regardless of what was in their path.
Typically, waves bounce and disperse when they meet any object. This causes the energy waves to scatter and become less intense as they move away from the object. It also makes transmitting data or energy using wave-scattering media almost impossible.
The new system allows sound waves to travel across such media without any distortion. It uses tiny speakers as acoustic relays to offset the wave scattering, and has been successfully tested on a real acoustic system. Their work has just been published in Nature PhysicsExternal link.
“We realized that our acoustic relays had to be able to change the waves’ amplitudes and phases at strategic locations, to either magnify or attenuate them,” Romain Fleury, head of EPFL’s Laboratory of Wave Engineering, said in a statementExternal link.
They tested their system in a 3.5-metre-long air-filled tube and inside placed various obstacles, such as walls, porous materials and chicanes. They then placed their tiny speakers between the obstacles and set up electronic controls to adjust the speakers’ acoustic properties.
“Until now, we only needed to attenuate sound waves. But here we had to develop a new control mechanism so we could also amplify them, like how we can already amplify optical waves with lasers,” added EPFL co-author Etienne Rivet.
Their new method uses programmable circuits to control several speakers simultaneously and in real time. It is similar to that used in noise-cancelling headphones and could potentially be used for sounds containing common ambient frequencies. It could also be used to eliminate the waves that bounce off objects like submarines, making them undetectable by sonar.
Popular Stories
More
Climate adaptation
Why Switzerland is among the ten fastest-warming countries in the world
Train vs plane: would you take a direct train between London and Geneva?
Eurostar is planning to run direct trains from Britain to Germany and Switzerland from the early 2030s. Would you favour the train over the plane? If not, why not?
This content was published on
Swiss companies are increasingly being targeted by cyber criminals. In the past quarter, every single company in this country was the target of a cyber attack an average of 1097 times a week.
Swiss households faced 21 minutes of power outages in 2024
This content was published on
End customers experienced an average of 21 minutes of electricity interruption in 2024. This resulted in 0.34 power outages per capita. The duration of electricity interruptions increased by three minutes compared to the previous year.
Swiss citizens will be voting on restricting wind farm expansion
This content was published on
On Friday, the Association for the Protection of Nature and Democracy submitted two initiatives aimed at curbing the expansion of wind farms. More than 110,000 signatures have been collected.
E-bike riders regularly break speed limit in residential areas
This content was published on
Fast e-bikes regularly exceed the speed limit in residential areas. According to a new study with data on cyclists in Zurich, they regularly reach speeds of over 30 km/h.
This content was published on
Swiss small and medium-sized enterprises (SMEs) are struggling to find staff, a problem made more acute by the increased bargaining power of employees and increased absenteeism.
Switzerland very close to tariff deal with the US, says Roche CEO
This content was published on
An understanding between Berne and Washington in the dispute over customs barriers is close: Roche CEO Thomas Schinecker is convinced of this.
This content was published on
Late on Thursday in Geneva, pro-Palestinian demonstrators attacked the Permanent Mission of Israel to the United Nations in the international organisations district. They poured red paint over the entrance to the building.
If you want to start a conversation about a topic raised in this article or want to report factual errors, email us at english@swissinfo.ch.
Read more
More
High-tech spear sheds light on Neanderthals’ hunting techniques
This content was published on
Using a high-tech spear, scientists in Zurich have established that Neanderthals used to kill animals at close range rather than throw their weapons.
This content was published on
Researchers in Switzerland have found a new cell type in the body’s fat depots which can actively suppress fat cell formation.
This content was published on
“Sonic umbrellas”, a hi-tech “cocoon” viewing booth and walls of speakers that soundproof better than concrete – the first results of the Montreux Jazz Digital Project that uses its unique archive footage for research have begun to emerge. At the rear of a studio at Lausanne’s ECAL design school in Renens a huge wooden honeycomb…
You can find an overview of ongoing debates with our journalists here . Please join us!
If you want to start a conversation about a topic raised in this article or want to report factual errors, email us at english@swissinfo.ch.