Voice Chat Issue

[Leuca]

Is it possible to have voice chat enabled without it picking up your microphone by default? I just had somebody complain about sound coming from my mic for the first time today since I started playing months ago. This same person however did not hear me say anything to the person next to me, nor could they hear me typing in response to their complaint, and my microphone is about a foot away from my keyboard.

 

I'm confused as to how this works, or if the person was simply experiencing a bug.