Researchers at Pennsylvania State University have developed a novel loudspeaker that can direct sound specifically at individual people – without those in the immediate vicinity hearing the same sound. The technology is based on what is known as an acoustic metasurface and could, in the long term, enable applications in security control centres, control rooms, vehicles, public spaces or personalised information systems.
The 3D-printed loudspeaker focuses sound with a precision similar to that of a beam of light. Whilst one person hears music or spoken information, the sound remains virtually inaudible to others standing nearby. The scientists refer to this as pinpoint acoustic control, which significantly surpasses the previous limits of conventional loudspeaker technology.
Sound is directed precisely
Conventional loudspeakers usually disperse sound waves widely throughout a room. This has been a physical limitation of acoustic systems for decades: sound propagates spherically and can only be controlled to a limited extent. The new development instead relies on a metasurface that specifically manipulates and focuses the sound.
Metasurfaces consist of specially arranged microstructures that can specifically influence waves. The principle was originally known from optics, for example in novel lens systems or camouflage technologies. Now the researchers are applying this approach to acoustics.
The unique feature of this development is that the loudspeaker does not simply emit sound, but actively focuses it spatially. This creates tightly defined listening zones. People outside this area perceive the sound barely, if at all.
New possibilities for security and control centre technology
This technology could become particularly significant for security-critical environments. In modern control centres, control rooms or KRITIS environments, numerous operators often work in parallel with different information flows. Until now, this has usually required headsets or spatially separated workstations.
In future, precisely focused audio channels could enable different staff members in the same room to receive individual acoustic alerts, radio information or AI-generated notifications – without interfering with one another.
Such systems would also be conceivable in emergency vehicles or mobile command centres. There, drivers, incident commanders and communications units could receive different information without audio sources overlapping.
Furthermore, the technology opens up possibilities for discreet information transmission in public areas. For example, safety-related instructions could be transmitted specifically to individual people or defined zones without broadcasting to the entire space.
Personalised acoustics instead of general sound diffusion
This development also signals a fundamental shift in audio technology. Whilst traditional loudspeaker systems are designed for wide-area sound diffusion, a market for personalised acoustics is increasingly emerging.
Companies are already experimenting with directional ultrasonic loudspeakers or beamforming-based audio systems. However, the new metasurface technology could make these approaches significantly more precise, compact and energy-efficient.
Added to this are advances in 3D printing. The researchers were able to produce complex acoustic structures that would be virtually impossible to create using traditional manufacturing methods. As a result, customised loudspeaker systems could be produced much more cost-effectively in the future.
Relevance for smart buildings and AI systems
This development also holds potential in the context of smart buildings and AI-supported assistance systems. In smart buildings, visitors or staff could receive targeted information depending on their location, role or authorisation.
Conceivable applications include personalised navigation instructions in airports, train stations or industrial facilities. Similarly, AI systems could provide discreet voice information tailored to the situation without disturbing others.
Particularly in security contexts, where information overload is becoming an increasing problem, the spatial separation of acoustic information could prove a decisive advantage. Instead of generalised alerts, warnings could be addressed far more precisely in future.
Acoustic control is becoming a key issue for the future
The development at Pennsylvania State University illustrates that the control of physical spaces is increasingly extending to the acoustic realm. Alongside video analysis, sensor fusion and AI-supported object recognition, the precise control of sound is thus also gaining strategic importance.
The technology is still at the research stage. Nevertheless, it serves as a prime example of how closely materials science, 3D printing and digital signal processing are now converging. For the security industry, this could, in the long term, enable entirely new forms of discreet communication and spatially intelligent information systems.
The loudspeaker of the future would then no longer be merely an audio source – but a precisely controllable tool for situation-dependent communication.
