Amazon.com Inc . is advertising its Alexa-powered speakers in the big game on Sunday. It’s an amusing 90 seconds that features celebrities like Gordon Ramsay, Rebel Wilson, Anthony Hopkins, Cardi B and the world’s wealthiest humankind, Jeff Bezos himself.

The word ” Alexa” is uttered 10 times during the course of its Super Bowl spot, but thankfully, the Amazon Echo in your living room isn’t going to perk up and try to respond. An Amazon spokeswoman is guarded about explaining exactly why, to say,” We do alter our Alexa ads … to minimise Echo devices falsely answering in customer’s homes .”

Bezos and company have obviously been thinking about this problem for a very long time, before the Echo was even introduced. A September 2014 Amazon patent titled” Audible command filtering “ describes techniques to prevent Alexa from waking up” as part of a broadcast watched by a large population( such as during a popular sporting event ),” annoying customers and overloading Amazon’s servers with billions of simultaneous requests.

The patent broadly describes two techniques. The first calls for transmitting a snippet of a commercial to Echo machines before it airs. Then the Echo can compare live commands to the acoustic fingerprint of the snippet to determine whether the commands are authentic. The second tactic describes how a commercial itself could transmit an inaudible acoustic signal to tell Alexa to ignore its wake word.

About a year ago, a Reddit user calling himself Asphyhackr did a little more legwork and concluded that Amazon was creatively employing the second largest technique. By running Alexa commercials through digital audio editing software, Asphyhackr discovered that Alexa ads transmit weakened levels of music in an upper section of the audio spectrum, between 3,000 and 6,000 hertz, outside the most sensitive scope of human hearing.

Asphyhackr speculated that Amazon could be tip-off Alexa off to dismis certain commands if it sees artificial gaps or bumps in the spectrum. To test his theory, he recorded person saying ” Alexa” and used a so-called band-stop filter that reduced frequencies merely in this high region of the spectrum. When he played out the recording,” My echo would not wake, even sitting right next to the speakers !” he wrote.

Amazon simply blogged about this topic and shed perhaps a bit more light on it. The corporation credited “acoustic fingerprinting technology that can distinguish between the ad and actual client utterances” and indicating that it advertising, engineering and science squads prepare for important events like the Super Bowl commercial, in order to suppress Alexa machines from addressed in it. When a major broadcast of the wake term “Alexa” is unanticipated — for example, when it’s mentioned on the” Tonight Show” — Amazon said its cloud servers can detect a match, create an audio fingerprint on the wing and can prevent 80 to 90 percent of devices from responding.

Whatever its method, Amazon has concocted a lane to ensure that Sunday’s commercial won’t merely be hawking Alexa. It will likewise be quietly telling tens of millions of Alexas to keep sleeping peacefully.