When Amazon’s celebrity-filled Alexa ad airs during the Super Bowl on Sunday, chances are it won’t wake your Echo speaker by accident. As Bloomberg reports, Amazon has figured out how to prevent Alexa from responding to wake words that it hears during commercials. The method likely involves dampening a high-frequency slice of the audio, and programming Alexa to ignore commands when those specific frequencies seem unnaturally quiet. Humans may not pick up on the difference, but Alexa’s microphones can.
Amazon patented that technique in 2014, along with an alternative approach that involves preemptive blacklisting of certain audio snippets that contain the wake word. But while either of those methods could prevent Amazon’s own ads from waking Alexa, they won’t stop outside forces from trolling Echo users on a grand scale.