Many asymmetric absorbers are currently based on a single-port system, where sound enters one side and is absorbed before a rigid wall. In this design, however, light and air are unable to pass ...

Metamaterials researchers have created a thin plastic structure with geometric details allowing it to control the redirection and reflection of sound waves with almost perfect efficiency.

IN the U.S. Bureau of Standards' Journal of Research for February 1930, pp. 289–296, there appears a description of apparatus employed by P. R. Hey I, V. L. Chrisler, and W. F. Snyder, for the ...