A startup called SonicNotify embeds inaudibly high-pitched audio signals within music or any other audio track. When a compatible app hears that signal, it triggers any available smartphone function to link you to websites, display text, bring up map locations, display a photo, let you vote on which song a performer plays next and so on.
Lady Gaga could have used its technology on her Monster Ball tour1, and Coachella 2013 and other events are next in line. To interact via SonicNotify, fans can use any SonicNotify-enabled app.
“With Sonic, we can unlock anything that your iPhone or Android can do, as long as the SonicNotify SDK is built into an app that’s running in the background on your phone,” explained SonicNotify. “For example, some of the stuff we’re doing with Gaga is when she is performing, mid-set, everyone in the arena gets a notification which lets them choose which song she plays for her encore.”
Why Lady Gaga Could Deploy a Sound Only Your Smartphone Can Hear [Wired]