Hello and welcome to SevenForums.
Here's a possible work-around you can play with.
I can listen to two audio outputs at the same time, but the audio is a bit out of sync between the two.
That may or may not matter to you depending on what you are listening to and how.
i.e. If listening to music in two different rooms, it may not matter that they are not in sync.
I never figured out how to sync them or if it's possible, but i never pursued that.
In Sounds / Recording enable "Stereo Mix"
In "Stereo Mix" properties:
- Check "Listen to this device"
- For "Playback through this device" select the 2nd audio device you want to use.
hope this helps.