Cannot get audio from both, the internal speaker and dock USB audio-out device

[pswiatki]

I am trying hard to get the internal speaker (of a DELL Precision 3561 laptop) and external audio-out (in the docking station) to work as audio outputs in Matrix. Everything I see suggests that the samples stream to the devices OK, but only one works at any given time. I found out that plugging in the headphones changes something in the system, and it is this device that goes red status in the Matrix:



When I attempt to Restart Audio Engine - I can sometimes see the status going white (OK) for a second or two, but then it changes back to red.

The built-in speaker always works, status is OK (not red). While I understand the issue might not have anything to do with any VB-Audio application, can anyone point me in the correct direction so that I can pinpoint the location of this automatic switching between the speaker and headphones (the OS is Windows 10)? I know the mini jack in the laptop itself is mutually exclusive with the built-in speaker, but the external USB audio (in the docking station) for sure is a separate device. I know that, because under Linux, I have no issues streaming to both, and they work independently.
Moreover, when I set the USB audio (in the dock) as the default device in Windows, it produces sound without any problems (still, mutually exclusive with the laptop's speaker). So, the device itself is OK.

[pswiatki]

I believe I found it, although more testing is needed:



I had both checkboxes checked. Now I unchecked them, and it seems to be doing what I needed. I shall test the behaviour more.
The sample buffer has changed when the device finally became alive:



Hope all is good, but if you have any comments, please let me know.

[Vincent Burel]

a problem on your device driver maybe ... strange.
otherwise use MME instead of WDM interface.

[pswiatki]

Thank you so much, Vincent. I shall try MME and report back.

[pswiatki]

Works very nicely with MME, and different audio streams can be routed to the two devices I mentioned above (say, radio on the speaker and YT streams on USB headphones.

[pswiatki]

otherwise use MME instead of WDM interface.

Would you be so kind as to point me to the proper place on the forum where I can learn more about WDM and MME (and, perhaps, KS)? I am interested in the technical sides of things.

[Vincent Burel]

MME is the first audio API coming with windows in the early 1990.
KS interface came with Windows 2000 or XP.
WDM = WASAPI appeared with Vista and was not working bad on WIN7