Introduction to the special issue on active and tunable acoustic metamaterials

Acoustic metamaterials are a class of architected materials with dynamic properties that are designed at the sub-wavelength scale to achieve exotic or unique macroscopic response. Although early concepts of acoustic metamaterials relied on static configurations, recent research has further expanded the limits of acoustic customization by incorporating active or tunable responses. This article provides an introduction to the special issues of The Journal of the Acoustical Society of America and J