A new spin on guiding sound waves along a one-way route

Acoustic device could cloak objects, jettison loud sounds

illustration of a proposed topological insulator

ON THE EDGE  Sound waves, shown in red and blue, are confined to the edge of a proposed acoustic topological insulator in these computer simulations. Sound moves counterclockwise from the source and easily navigates sharp turns (top). 

Z. Yang et al/Physical Review Letters 2015 

An array of miniature turntables could offer a powerful new way to control the flow of sound.