Re: VOIP is coming through my speakers, not my headset.
It's been suggested that the solution is to disable drivers for audio devices not in use - Specifically Nvidia audio drivers. In my case there were two Nvidia audio device drivers plus the motherboard audio device that were not in use. I've disabled all of those and left my main audio interface and my headset.
Now it's so damn rare to find anyone in BF1 actually using a headset that I have not been able to test to see if this is working. If anyone else is able to test and confirm, please let us know.
To those who keep asking which platform we are playing on - it's PC. YOu can tell because we're talking about things like drivers and default playback devices. Try to keep up.