Invisibility cloak gives sound performance

Physics World - 13 January 2012

"By drilling holes in a piece of PVC and then filling them with soft plastic, scientists in Germany have built a device that can effectively make objects invisible to sound waves. The performance of the acoustic "invisibility cloak" exceeds that of existing electromagnetic devices and could open up new ways of manipulating waves, including the development of shields against seismic waves... John Pendry [Physics] of Imperial College London, who put forward the first design for an electromagnetic invisibility cloak, describes the latest results as 'an impressive achievement'"

http://physicsworld.com/cws/article/news/48287