from Hacker News

Ask HN: Why does my laptop audio turn on when I log into Facebook?

by entangld on 1/25/16, 3:07 PM with 4 comments

• by explorigin on 1/25/16, 3:30 PM

  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.

• by lsiunsuex on 1/25/16, 3:27 PM

  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.