In addition to the Nvidia device look for any other extraneous audio devices in the device manager and disable them. For example, every time my RiftS updates it installs a virtual audio device that I assume from what I've read is something really for the Quest. The FB genii decided last year to unify all their software so that's why I get it whether I have a Quest or not. Disabling that immediately following an update has become SOP along with going into my OBS audio settings and rearranging my audio sources as that update always scrambles them.
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