More interesting is when we used to run Alexa commercials and it would cause a denial of service attack on ourselves with all the devices being triggered, particularly during the superbowl. In that case, we added some imperceptible noise to the audio stream so that Alexa wouldn’t trigger.
Ask HN: How does Alexa avoid interrupting itself when saying its own name?
11–20 of 61 posts
Re: Ask HN: How does Alexa avoid interrupting itself when saying its own name?
#12What happens if you record her saying her own name and then play it back separately? Does she respond to that if she's not actively talking at the moment? ----- Not directly the same case but similar, Amazon trains Alexa to avoid certain mentions of her in commercials using acoustic fingerprinting techniques: https://www.amazon.science/blog/why-alexa-wont-wake-up-when-...
> What happens if you record her saying her own name
I suggest we don't personify devices.
Re: Ask HN: How does Alexa avoid interrupting itself when saying its own name?
#13spitballing: 'her' own hardcoded waveform is a hardcorded wake word exception. i have doubts that it'd be much more complex than that. what i do find interesting, however, is that, at times, she'll wake to an utterance from some other media i have playing and seems to 'know' immediately that she was inadvertently awoken. the 'listening' tone and 'end listening' tones sound in quick succession. i do not have voice rec…
> seems to 'know' immediately that she was inadvertently awoken. the 'listening' tone and 'end listening' tones sound in quick succession
Speculation:
- To reduce latency, the "listening" tone plays as soon as the wake word chip hears the wake word
- To improve accuracy, the wake word chip keeps a circular buffer of the last couple seconds of audio, and the main CPU / DSP scans that when it wakes up
So you get spurious wakeups exactly the same as a human - You think you hear something, then you re-listen to it in your mind and realize it was something else.
Re: Ask HN: How does Alexa avoid interrupting itself when saying its own name?
#14Ive always thought they might have a method to ignore the wake work if theres a specific frequency sent at the same time. I’ve noticed that there are sometimes TV commercials that have the “alexa” or “hey google” wake words, but they do not activate the smart speakers. But if the smart speakers hear something close on just a random tv show they will activate.
But as others have said, they might be able to just sleep the wake algorithm temporarily when they know it’s playing back its own wake word.
Re: Ask HN: How does Alexa avoid interrupting itself when saying its own name?
#15The simple solution: switch off the code that listens for the “Alexa” prompt when saying “Alexa” yourself. Slightly harder: keep it running, but discard hits that are timed close to the time you say “Alexa” yourself. Even harder: have a second detector that is trained on the device saying “Alexa”, and discard hits that coincide with that detector firing. That second detector can be simplified by superimposing a wavef…
I’ve interrupted my Echo with “Alexa, stop” or “Alexa ” while it is speaking. So it doesn’t stop listening when speaking.
Re: Ask HN: How does Alexa avoid interrupting itself when saying its own name?
#16Not speaking for Alexa or Amazon, where I have worked in the past, but the wakeword detection is done separately in a much lower power, localized model using hardware features. On the downside this means that you can only select from a few wakewords and the filtering etc. are limited (e.g. the local model is not aware of commercials being played concurrently in the world, so has to wake up the bigger model, which can check to see if that's happening). On the positive side, it's much lower power and mitigates concerns that Alexa is listening to normal activity/conversations.
Re: Ask HN: How does Alexa avoid interrupting itself when saying its own name?
#17Pre-generate a waveform in exact opposite of the utterance. Add it to the incoming waveform.
Re: Ask HN: How does Alexa avoid interrupting itself when saying its own name?
#18[deleted]
Re: Ask HN: How does Alexa avoid interrupting itself when saying its own name?
#19The simple solution: switch off the code that listens for the “Alexa” prompt when saying “Alexa” yourself. Slightly harder: keep it running, but discard hits that are timed close to the time you say “Alexa” yourself. Even harder: have a second detector that is trained on the device saying “Alexa”, and discard hits that coincide with that detector firing. That second detector can be simplified by superimposing a wavef…
They'll definitely do some cancelation of the signal they're sending, you can't really hear people saying commands over your own music otherwise.
Re: Ask HN: How does Alexa avoid interrupting itself when saying its own name?
#20The simple solution: switch off the code that listens for the “Alexa” prompt when saying “Alexa” yourself. Slightly harder: keep it running, but discard hits that are timed close to the time you say “Alexa” yourself. Even harder: have a second detector that is trained on the device saying “Alexa”, and discard hits that coincide with that detector firing. That second detector can be simplified by superimposing a wavef…
I’ve interrupted my Echo with “Alexa, stop” or “Alexa ” while it is speaking. So it doesn’t stop listening when speaking.
It could stop listening only when it's saying the word "Alexa", or even just part of that word, and listen the rest of the time.