That's interesting... I would have to look into this a bit more, I am curious. I did some searching, though, and found this old post and someone said they solved it by doing this:
"For anyone wondering, I fixed this problem by disabling all NAHIMIC processes in task manager.". Searching this, the process is called nahimicservice.exe. Found on a couple of brands of computers. Not sure if that's your case or not... if not, what do your audio properties look like? I wonder if it's something permission-related, since I think EAC would be using elevated privileges, so the game would be allowed to communicate. Inital thoughts, would have to dig a little further, but wanted to put them out here in the meantime.
If you're not sure how to get to the audio settings, here's windows 10:
Right-click on the volume icon on the taskbar and then click Sound to open the Sound dialog.
Under the Playback tab, right-click on your speaker and then click Properties.
You will see the Speakers / Headphones Properties window with different tabs, such as General, Levels, Enhancements, and Advanced.
You can adjust various settings for your speaker, such as the default format, the balance, the sound effects, and the exclusive mode.