Acoustic Diode Only Lets Sound Travel in One Direction (Read: True Soundproofing)
The Acoustic Diode By tuning the elastic spheres in certain ways--by changing their sizes and shapes from one end of the chain to the other, for instance--it's possible to manipulate a sound wave as it travels down the chain, downshifting the frequency or making it possible for sounds to travel in one direction but not the other. Chiara Daraio/Caltech Anyone who has ever tried to record that first feature-length album in his or her dad's garage knows that reflecting, suppressing, and otherwise manipulating sound isn't as simple as it might seems. We've got that egg-carton foam that offers some soundproofing, but beyond such muting materials we have few mature technologies that let us control the way sound travels. But Caltech researchers are working to change that via the first tunable, acoustic diode that can be used to let sound flow in one direction only. The acoustic diode works much like the electrical...