Ask HN: Why does my laptop audio turn on when I log into Facebook? - entangld
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explorigin
I recently read about ad-sources correlating smartphones with desktops via
transmitting ultrasonic tones that another device can listen for. I can't find
the article now but it was mentioned on HN a few days ago...perhaps in a
comment.

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lsiunsuex
That's pretty vague. PC? Mac? Chromebook? OS version? Browser version?

Could be a browser extension; FB app you gave access to; malware; any number
of reasons a website could access audio devices on your machine.

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entangld
Signed into FB from Chrome (version 47) from my MacBook (Mavericks).

It was 6am and I had my earbuds in and I could tell they turned on. They
didn't turn off until a few minutes after I logged off.

I went to YouTube just to check. A few minutes after I closed my YouTube tab,
I could hear the audio disengage.

I'm wondering if it's connected to FB autoplay videos, but those have no
sound.

~~~
lsiunsuex
Just did the same test and I'd say it's auto play videos.

(same setup - current Chrome / current OS X)

I turned on auto play videos, killed the browser, waited for my headphones to
turn off and went back into FB - scrolled down and when a video came into
view, the headphones turned on.

Even though the video might have no sound, the html 5 video element still
needs to allow sound to pass through. When videos auto play without side, it's
not that the video doesn't have sound; it's just that the video has been muted
until you click on it.

(speculation of course; I don't work for FB)

