It is different to the one you get if you type 'Sound mixer' in the start bar.This brings up a panel called 'Volume Mixer', which is an evolution of the one found on most platforms.Right click on the audio icon task bar and select 'Open Volume Mixer', which brings up a window you can resize, showing 'Device' and 'Applications'.
To confirm this, I had to go to a unique panel as follows: My symptoms were identical to the reported ones in the main post and replies: Spotify desktop app was not audible on only one particular audio output device, while all other app sounds and other outputs were working. I believe I've found the (a?) root cause: the spotify app was specifically muted on the problematic output device within the windows 10 settings.
