on Win10 1709 i have driver from 28/09/2017 #10.0.16299.15 and have issues with audio:
sometimes the microphone in the system (win) recording devices does not show the sound level, tried to turn on / off the button on the right earpiece, deleting vive audio driver and reinstal - it does not help.
in the SteamVr and in the Discord, a suitable recording device is selected. It looks like a driver / firmware problem.