BU engineers have developed an “acoustic metamaterial” that can cancel 94 percent of sounds.

City life is so noisy, you have to find a way to create quiet moments, they say.
That got them dreaming up a sound baffle that wasn’t a barrier at all, but instead an open conduit. Such a feat could only be possible by developing a material with unusual and unnatural properties (known as a metamaterial), in this case with the ability to exert an isolated influence on sounds—an acoustic metamaterial.