Amazon has found a clever way of not accidentally awakening the Alexa-powered speakers.
But this weekend, Amazon's 90-second Super Bowl commercial used the word "Alexa" just three seconds in, and the vast majority of Echo speakers will have ignored it completely.
To avoid every Amazon Echo within earshot of the big game and the relevant ads, Amazon actually taught Alexa to ignore the wake-up command it so readily responds to.
The effort to arrive at a solution dates back to 2014, when Echo was nowhere in the picture.
A Reddit user did some digging into an Amazonpatent from 2014 past year to find out that the company transmits an inaudible acoustic signal to basically let Alexa know that it should ignore this particular instance of its wake word. In a blog post, Amazon explained, "This is possible because of acoustic fingerprinting technology that can distinguish between the ad and actual customer utterances".
Amazon acknowledges that the dynamic fingerprinting isn't ideal, but up to 80% to 90% of devices won't respond to the broadcasts thanks to the dynamic creation of the fingerprints.
Of course, the dynamic fingerprinting can not fight all the incoming trigger words, so it will work on 80-90% devices.
Amazon just blogged about this topic and shed perhaps a bit more light on it. However, a tech enthusiast on Reddit seems to have dug out the secret, according to Bloomberg.
It seems that Echo is not processing the wake word if it's as quiet as 4000hz to 5000hz.
Tweaks like this help Alexa to hold a firm ground against rivals.
The premise of the ad, which imagines the company's efforts to find a replacement if Alexa ever lost her voice, is simple and sets up the company to ripe for future entertaining ads and perpetuate the Alexa business model. "It's a very positive surprise for us".