At a Glance
- Researchers developed a device that acts like a prism for sound, passively separating mixed audio signals into their distinct frequencies by using only its unique physical structure.
- This innovation draws inspiration from biological structures like animals’ intricate ears, which have evolved to passively shape and direct sound waves with remarkable natural precision.
- The team designed the emitter’s complex shape using computational morphogenesis, combining powerful computer algorithms with accurate wave simulations and modern 3D printing to optimize acoustic properties.
- Operating entirely on passive scattering, the device requires no electricity and manipulates sound waves solely through physical interaction between the audio signal and its precisely engineered solid surface.
- This research establishes a method for precisely controlling sound fields, opening possibilities for innovative, energy-free devices in disciplines such as acoustic sensing, imaging, and telecommunications.
Researchers have developed a novel device that splits a mix of sounds into its constituent frequencies, essentially creating an “acoustic rainbow.” In a study published in Science Advances, a team from the Technical University of Denmark and Universidad Politécnica de Madrid unveiled the Acoustic Rainbow Emitter (ARE). This single, solid object, created without any electronic components, takes in a wide range of sound frequencies from a single point source and passively scatters them. The result is that different pitches are directed to specific locations, much like a glass prism that separates white light into a spectrum of colors.
This achievement marks a significant step in sound manipulation, a field where nature has long outshined human engineering. Organisms from bats to dolphins have evolved intricate biological structures, such as the outer ear or pinna, that passively catch and shape sound waves with remarkable precision for navigation and communication. In contrast, most human-made systems have struggled to replicate this ability across various frequencies. Artificial sound control typically relies on active systems that require electricity and complex electronics or resonance-based structures that only work well for a narrow sound band.
The research team turned to a powerful design method called computational morphogenesis to bridge this gap. This process uses sophisticated computer algorithms to generate complex, highly efficient shapes inspired by how structures grow and form in nature. By combining this approach with accurate wave modeling—using a mathematical tool called the Helmholtz equation to simulate sound propagation—and modern 3D printing, scientists could iteratively design and test a solid material’s shape. This allowed them to fine-tune the structure until it could passively manipulate sound waves to match a specific directional pattern.
The final devices, which include the ARE and a similar “lambda splitter” that separates high and low pitches, operate on the principle of passive scattering. This means they require no electricity, manipulating sound purely through the physical interaction between the sound waves and the object’s intricately designed surface. This research establishes the potential of computational morphogenesis to shape how sound is emitted and received precisely. By enabling the design of complex, energy-free structures, this approach opens new doors for innovation in disciplines focused on wave sensing and control, from acoustics to telecommunications.
References
- Christiansen, R. E., Fernandez-Grande, E., & Sigmund, O. (2025). Morphogenesis of sound creates acoustic rainbows. Science Advances, 11(24), eads7497. https://doi.org/10.1126/sciadv.ads7497
- Mondal, S. & Phys.org. (2025, June 13). 3D-printed device splits white noise into an acoustic rainbow without electricity. Phys.Org; Phys.org. https://phys.org/news/2025-06-3d-device-white-noise-acoustic.html
