The authors tested the 3D-printed meta-earplug on an artificial head and a group of human participants, demonstrating an effective reduction in low-frequency sound. WASHINGTON, April 28, 2026 — ...
Immersed in a vast, open plain, this low-frequency growl emanates from a powerful marsupial, its resonant vibrations threading through sun‑washed grasses and cracked earth. The deep rumble rises ...