FALMER, United Kingdom (AFP) — A super material made of tiny 3D-printed bricks will allow people to create their own acoustics by diffracting, scattering and refracting sounds, using their own do-it-yourself kit, say British-based researchers.
Scientists at the universities of Sussex and Bristol created 3D printed metamaterial bricks which bend, shape and focus sound waves that pass through it. Each individual brick works by slowing down the sound through a series of flaps that coils the incoming sound waves so that they can be transformed into any required sound field.
Dr Gianluca Memoli, from the Interact Lab at the University of Sussex, led the study. Memoli says that the team has created a sonic ‘alphabet’ of 16 individual bricks needed to create any sound thinkable.
“We have discovered that you just need 16 bricks to make any type of sound that you can imagine, just like you create any words with 26 letters,” Memoli told Reuters.
The negative refractive index found in the synthetic composite material gives it properties not usually found in natural materials.
“We identified the positions of the flaps that are most used – like the letter E in our language. That’s amazing, because if you tell me which sound you want, with what precision you want, I can tell you which bricks to use to put in front of your loudspeaker to achieve that effect,” said Memoli.
Professor Sriram Subramanian, head of the Interact Lab at the University of Sussex, told Reuters acoustic devices could manipulate sound just as easily as LCDs and projectors do with light.
Small versions could have important medical application, such as focusing high intensity ultrasound to destroy tumors deep within the body.
“In a year we could have a sleeve that we can put on top of already existing projects in the market and improve them,” he said. “For example, we can have a sleeve that goes on top of ultrasound pain relieving devices that are used for muscular pain. So we could have three types of sleeve – one that treats shallow pain, one for medium depth pain, and one for pain that is close to the bone.”
Such metamaterial layers could be tailor-made to fit individual patients’ bodies and tuned to focus the ultrasound waves.
Large versions could be used to form an audio hotspot by directing or focusing sound to a particular location.
“You could strap a static piece on top of existing speakers and direct sound in two different directions without any overlap. The passengers in a car could hear completely different information from the driver,” said Subramanian.
Such a device could be developed within six or seven years, he believes.
Subramanian says fully digital spatial sound modulators could be controlled in real time with minimal resources, and will push the boundaries of metamaterials, allowing them to perform nature-defying tasks.