[cowsandmilk]

siri has itself trained to a single user's voice. I've never had anyone else's voice activate my phone with "Hey Siri". Admittedly, it usually takes me saying "Hey Siri" 3 times before it recognizes my voice, but I'm 100% certain a radio ad would get no response from my phone.

[robterrell]

Siri is definitely not trained to a single voice. And yes, the car radio can turn it on. I've had a podcast discussion of Siri trigger it. It became such a joke that some podcasters have another phrase they say when they mean "hey Siri".

[Artemis2]

Since the iPhone 6S, Hey Siri is activated by a dedicated chip in the SoC. This enables low-power real-time detection of trigger words. Before, Hey Siri only worked with phones in the process of charging, because it was done with software, so a lot less efficient.

These voice-activated chips can be trained (as seen in a lot of other phones), but I'm not sure the software-powered Siri can be trained.

[XorNot]

"Trained" is a bit of a joke with voice-activation. I've never seen it matter in practice.

[gherkin0]

Doesn't "trained" in the context of voice recognition mean something more like "better able to understand your voice" and not "able to exclude other voices."

[dorfsmay]

I think Google does for android. I often ask "wake me up in 15 minutes". I've seen the phone write 50 and immediately switch to 15.

[knn]

trained to a particular voice ~= trained to a user's preferences!

[fencepost]

As a sample of the alternate term, Merlin Mann's assorted podcasts generally use "Ahoy Telephone."

[legulere]

It has only been a feature since iOS 9: http://9to5mac.com/2015/09/11/os-9-siri-voice-recognition-tr...

[glitch003]

Just want to chime in and say that I can activate my girlfriends iPhone by saying "Hey Siri" in a girly sounding voice. It's trained to only her voice but I can trigger it. So it's not foolproof as you make it seem.

[ianferrel]

My wife's phone regularly (maybe once a month), starts listening in response to me saying something, which isn't even "Hey Siri", despite never training with my voice. My voice does not sound anything like my wife's.

So, I think the error rate is simply not low enough to make conclusive claims about what it might or might not do.

[madeofpalk]

It happens to me many times a day. I've b come acutely aware of how much I question other people because it activates when I say "Are you serious?"

[JetSpiegel]

Better stock up on those tinfoils.

[foota]

I have an acquaintance by the name of Siri, hilarity ensues.