I recently acquired the Arctis 9 Wireless headset which was not working in Starcraft2.
When I launch SC2, my entire computer ends up muted, including Chrome , audio tests, etc.
The problem relates to the fact that the Arctis 9 has 2 audio output otptions, game and chat.
If you disable the chat output, everything functions as normal, however, this is FAR from ideal as this is a really nice feature of the Arctis 9 Wireless.
It seems like SC2 is choosing the Chat option for the game instead of the Game audio option. Everything is set up correctly in Windows settings and all other games work.
SOLUTION:
After quite a bit of fiddling around I eventually found a really simple fix.
SC2 likely does not really understand the 2 audio out options, so what you need to do is:
In SC2, go to Options > Voice Chat > Output Device
and select “Arctis 9 Wireless Game” as the output for ingame voice chat.
This is not the complete ideal solution, but I never use the Voice Chat in SC2 and stick with Discord any way.
Hope this helps someone else.