Alexa purposefully ignoring her name might seem like unexpected sass from Amazon’s virtual assistant, but it’s a key part of the retailer’s big Super Bowl promotion this coming weekend. The assistant will take center stage in a celebrity-filled commercial at the ball game, but if you’re already an Echo owner, you’ll be pleased to hear that Amazon has figured out how to avoid its spot inadvertently activating your smart speaker.
It’s something that has become an unexpected cause for concern among always-listening speaker owners in general. Commercials pitching Google Home, for example, have been blamed for triggering the gadget with the “Ok Google” phrase, not to mention scare-stories of accidental purchases started by mentions on TV. With ten “Alexa” mentions in the Super Bowl advert alone, that would be a lot of interruptions should it happen within earshot of your Echo.
However, Bloomberg reports, Alexa will be smart enough to ignore her big moment on-screen. According to a patent filed by the company, it in effect pre-warns each Echo device with a section of the audio from the commercial. That’s then used as a fingerprint for what Alexa should avoid.
While each mention of the wake word might sound identical to our ears, the Echo’s microphone array and processing is able to tell the difference between the acoustic fingerprint of the mention in a commercial, and that of a real command in the room. That way, your Echo can ignore what it’s hearing from the TV.
It’s not Amazon’s only idea, mind. The patent also suggested using an acoustic signal which would be out of the hearing range of us humans, but audible to an Echo. With that playing, Alexa would know that it wasn’t a real trigger.
Making sure the right Echo hears its wake word, and the right Echo responds, has required some serious audio cleverness by Amazon’s engineers. One of the retailer’s goals has been to get as many Echo devices into a home as possible, on the understanding that people will be more likely to use the smart speaker if it’s within speaking range wherever they happen to be. Of course, that then introduces the possibility of multiple Echo devices trying to respond simultaneously.
The solution is something Amazon calls “Echo Spatial Perception,” or ESP, and it means that even though a single “Alexa” wake word might set multiple Echo units listening, only the one nearest you should actually respond. For the Super Bowl, of course, Alexa will go even further than that, and ignore her name altogether.
Update: Amazon has confirmed that it’s using acoustic fingerprinting, though not quite in the same way as the patent describes. Rather than pre-warning each Echo about what it could expect to hear, the audio fingerprints are built on-the-fly. If multiple Echo speakers wake simultaneously, such as because they hear “Alexa” on a broadcast, an algorithm in the cloud spots that and, if matching audio from different devices is confirmed, can prevent other Echo units from responding. Although some Echo units will respond, therefore, 80- to 90-percent will ignore the false trigger, Amazon claims.