Researchers at Penn State have developed a groundbreaking “audible enclave” technology that creates sound pockets audible only at specific locations. The innovative system, detailed in a recent publication in the journal Proceedings of the National Academy of Sciences, utilizes ultrasound waves to deliver targeted audio experiences.
The technology works by employing ultrasound waves that travel silently through space, becoming audible only at the intended destination. These waves can be manipulated to navigate around obstacles, effectively creating a “virtual headset” effect with distinct sound and quiet zones for targeted listening.
One of the primary challenges faced by the research team was the diffraction of sound waves. To overcome this, they implemented a novel approach using two ultrasound beams as carriers for audible sound. The researchers also introduced the concept of bending ultrasound beams through “acoustic metasurfaces,” drawing parallels to how optical lenses bend light.
The transformation of ultrasound into audible sound occurs through the projection of beams at different frequencies. For instance, beams at 40,000 Hz and 39,500 Hz intersect to create a new audible sound wave at 500 Hz. This technique allows for precise control over the audio output.
To validate their findings, the team conducted tests using a simulated head and torso dummy equipped with microphones to mimic human hearing. The results confirmed that the sound was indeed only audible at the point of intersection of the ultrasound beams.
Currently, the technology can create audible enclaves at a distance of approximately three feet, with a volume of around 60 decibels. While still in its early stages, the potential applications for this technology are vast, particularly in public spaces where providing sound to specific groups without disturbing others is desirable. Additionally, it could play a role in noise-cancellation efforts in urban environments.
As research continues, the scientific community expresses excitement about the future possibilities of this audible enclave technology. However, it is important to note that the system is still in the early phases of development, with further refinements and advancements expected in the coming years.
