The Sound Dampening Metamaterial Cloak

Researchers at Duke University have developed...  ...erforated plastic sheets that successfully dampen sound . The cloak is designed to prevent sound from traveling forward by guiding the sound waves through holes in the plastic sheets, thereb...  ...microwaves they should b...

http://www.neatorama.com/2011/07/08/the-sound-dampening-metamaterial-cloak/