In the Audio Volume Settings under the tab "Output Devices" it is possible to set the default device. I have the following configuration: 1 laptop 1 dockingstation When the laptop is connected I set the default audio output device to soundcard of the dockingstation. When I disconnect the laptop the new default output device is the built-in soundcard. Wish: It would be nice if the laptop is reconnected again, the default output device is switch back to the original default.
Can you try the new "switch on connect" config option in Plasma 5.8.
I activated "Audio Volume Settings" -> "Audio Volume" -> "Configuration" -> "Automatically switch all running streams when a new output becomes available". Undocking the running notebook switches to built-in sound card. Put on docking station again activates the docking station sound card. So this seems to work. I will also test what happens if I shut down the notebook before re-docking again and report back with the result.
The second test was also successful.