3 min read
0 comments
Created by researchers at Pennsylvania State University, the innovation uses ultrasound to create invisible sound enclaves, where sound is audible only to the listener. The technology could transform public spaces, offices, public transportation and the advertising sector.
Listening to music on the subway or watching videos in a coffee shop without headphones and without disturbing others around you may seem impossible — but it’s not anymore. A team at Penn State University in the United States has developed a new technology that precisely directs sound to a single point in space, allowing only the user to hear the audio, even in public places.
The research was published in March 2025 and caught the attention of media outlets such as Olhar Digital and the website Terra, which explain that the innovation works through so-called non-linear acoustics, creating silent “sound zones” for those out of range. The sound curves, avoids obstacles and reaches the listener’s ear with precision, without external noise or interference for other people.
How does technology that eliminates the need for headphones work?
The solution is based on ultrasound beams, which interact with each other until they form an audible enclave — that is, an exact point where the sound can be heard. The researchers explained to the journal Applied Physics Letters that, outside of this point, the beams remain at frequencies inaudible to humans.
- Many people are surprised to discover that aluminum foil can be used to improve the Wi-Fi signal at homeSS
- New combustion engine could revolutionize electric cars and is already attracting interest in the industry
- New Chinese cell phone brand arrives in Brazil with 5G line, 6.500 mAh battery and 90W charging
- A giant hole — the size of Switzerland — has appeared in Antarctic sea ice
Acoustic engineer Amir Eftekhar Azam, one of those responsible for the study, said the intention was to create a private audio system, without physical isolation, ideal for personal use or in shared environments. According to him, “this technology can transform the way we listen to music, participate in virtual meetings or even receive advertising information in public places”.
Applications: from the office to public transport
Practical applications already mapped out include subway stations, waiting rooms, shared offices and even autonomous vehicles. Since the sound is only audible to the recipient, it would be possible to listen to a call or video without the need for headphones or speakers. Corporate environments would also benefit from greater privacy during calls and less overall noise.
According to the Terra portal, companies in the technology and advertising sectors have already shown interest in the new technology. The possibility of creating “sound bubbles” targeted at specific consumers could pave the way for new interactive advertising formats in shopping malls, airports or sporting events.
Challenges and next steps
The Penn State team acknowledges that there are still challenges. The first is the size of the equipment, which currently occupies a lab bench. The next phase of the project involves miniaturizing the ultrasonic emitters and increasing their targeting efficiency.
Another crucial point is regulation. Since the system works through ultrasound, it will be necessary to follow safety standards and use in public spaces. The US Federal Communications Administration (FCC) is already studying standards for directional sound technologies that could be used commercially.
