The Coke can acoustic lens, surrounded by speakers, can focus sound waves to a space 1/25th the size of a wavelength. Image credit: Fabrice Lemoult (PhysOrg.com) -- When trying to focus sound waves ...

Sound, like light, can be tricky to manipulate on small scales. Try to focus it to a point much smaller than one wavelength and the waves bend uncontrollably--a phenomenon known as the diffraction ...

We saw earlier that when sound waves come from correlated sources then their pressure and associated velocity components simply add. This meant that the pressure amplitude could vary between zero and ...

Sound system: photograph showing the array of loudspeakers on the far left. Also visible are the metamaterial lens of plastic spheres and the microphones used to acquire the images. (Courtesy: ...