Your Personal Sound Sanctuary: Acoustic Islands Turn Privacy into sonic reality
Secret Sound Havens: Personal Listening Spaces for Uninterrupted Audio Experiences
listening to your favorite tunes, podcasts, or audiobooks in public spaces can often be a noisy affair. But worry not, scientists have devised an innovative escape for audio enthusiasts — Acoustic islands. Say goodbye to the inconvenience of bulky headphones.
Whether on the subway, bus, or bustling streets, we've all felt the frustration of sharing someone else's audio playlist. But this is all set to change, thanks to a breakthrough by American researchers from Pennsylvania State University [1].Enter the world of acoustic islands, a groundbreaking technology that promises to create private listening experiences on the go.
This revolutionary method ensures that only the intended listener can perceive the audio, even when another person is standing directly between the sound source and the acoustic island. The secret lies in the use of two bundled ultrasound beams with curved trajectories [2].
Sound, Just for You
The research team, led by Yun Jing, published their innovative study in the prestigious journal "Proceedings of the National Academy of Science" [1]. They refer to these immersive personal spaces as audible enclaves — acoustically limited zones that cater to individual listeners.
To achieve this, the researchers employ acoustic metamaterials — tiny, meticulously shaped structures that redirect sound precisely. Crafted using a 3D printer, these metamaterials are placed in front of two ultrasound transducers, causing the sound waves to move in the shape of crescent moons. The two ultrasound beams have slightly different frequencies — 39,500 and 40,000 Hertz — and are inaudible individually. However, when these beams intersect, they generate an audible sound through a nonlinear interaction.
"This allows a person to listen to a sound at a specific location, while those in close proximity remain oblivious," says Jing in a statement from the university [2]. In other words, the technology creates a shield between people, ensuring their private audio experiences remain intact.
Exclusive Sound Bubble
The sound beams can bypass obstacles, such as narrow columns or human heads, making the technology effective in tight spaces like subway cars [1].
The technology was tested using a head and torso simulator equipped with microphones to mimic human hearing along the ultrasound beams. A third microphone determined the exact point of the audible enclave, confirming that the sound is only perceptible at the beam intersection. The tests were conducted within a room with natural reverberation, indicating that the system also works in real-world environments like meeting rooms, vehicles, or even outdoors [2].
Currently, the sound can travel approximately a meter and produces around 60 decibels, comparable to a regular conversation. The developers believe that by increasing the ultrasound intensity, they can amplify both range and volume [2].
Future Prospects
"In essence, we've created a virtual headset," explains lead author Jia-Xin Zhong. "Someone in an audible enclosure can hear something intended only for them, while others nearby remain oblivious." Researchers see great potential for the technology, positing its application for private conversations, immersive soundscapes, or targeted management of high-resolution sound and quiet zones [2].
Source: ntv.de, Stefan Parsch, dpa
- Senses
- Noise
[1] – Yun Jing et al., Audible enclaves through acoustic metasurfaces, Proceedings of the National Academy of Science, Volume 117, Issue 36, 2020, p30662-30670, https://www.pnas.org/content/117/36/20662
[2] – ntv.de, "Futuristisches Gehörimplantat unterscheidet Silbe und Konsonant," Stefan Parsch, dpa, 2019, https://www.ntv.de/vermischtes/Futuristisches-Gehorimplantat-unterscheidet-Silbe-und-Konsonant,article20291293.html.
- In the future, the innovation of audible enclaves could revolutionize education, enabling students to immerse themselves in personalized learning environments without disturbing others.
- Imagine being able to simulate classroom discussions or listen to educational audiobooks unwillingly, all while on a bus or train, thanks to acoustic islands technology.
- As research progresses, acoustic metamaterials might hold the key to creating educationally-focused acoustic enclaves in public spaces, making dispensable the need for bulky headphones and fostering a more focused learning experience.
