This talk by Woody Norris ( no actual link to my blogs name, just coincidence ) is actually remarkable. It’s from 2009 but the technology he is showing has so many applications. Being able to focus sound into directions and separate ears can have applications across medical,  leisure and daily life. You know the situation when your on the sofa and someone wants to watch a film while the other is working, being distracted by the noise. Hypersonic sound would allow one person to watch the film while the other person could work and listen to music while only being a few feet away from each other. This was displayed in TED Jan 2009 andI havent seen anything on the consumer market yet which is disappointing, but hopefully soon hypersonic sound will break through in daily life. Now go listen to Woody and he will explain some amazing applications for the invention! enjoy!