If you’re an Alexa owner who's ever wondered why TV ads don’t wake your smart speaker – especially during Super Bowl LII – it’s because Amazon’s been doing some clever work in the background.
A mixture of voice matching specific snippets of ads and inaudible clues added into adverts ensures that your Alexa won’t be irritatingly awoken by TV adverts for the system.
In fact, it’s all part of an acoustic fingerprinting technology patent by Amazon titled “audible command filtering”, registered back in September 2014. The company foresaw the problem of millions of Amazon Echos being inadvertently awoken by media, including TV ads and large televised events – just like the Amazon’s star-studded commercial during the Super Bowl. Why so problematic you ask? Not only would that be annoying for owners, but it could potentially overload Alexa’s servers.
So Alexa's protective algorithm works in two ways: specific audio can be uploaded by Amazon, matched and ignored by Echos. That’s easy to do when Amazon has the specified audio for its own ads. But there’s a second method, which would stop third parties from manipulating the voice assistant.
An algorithm produced by Amazon can detect a spike in simultaneous Echo awakenings, examine the audio, and then send out a call for devices to ignore that specific command in a split second.
In a blog post about Amazon’s Super Bowl advert, Amazon director for speech recognition Manoj Sindhwani explained further:
“An algorithm within Amazon’s cloud detects matching audio from distinct devices and prevents additional devices from responding. The dynamic fingerprinting isn’t perfect, but as many as 80 to 90% of devices won’t respond to these broadcasts thanks to the dynamic creation of the fingerprints,” he said.
So if your Alexa slept through the Super Bowl last night, that was thanks to years of planning and engineering – and offers a glimpse into the challenges of getting voice assistants behaving properly in our homes.