UD-3900 No sound from Speakers built into Monitor

I have a Lenovo ThinkPad X1 Carbon running Windows 10 connected to my UD-3900 via USB and then to the monitor via HDMI. I can’t find a way to get sound to come from the speakers. If I disconnect the HDMI cable from the UD-3900 and connect it directly to the HDMI on the monitor all works fine. I would prefer NOT having to connect the HDMI to my computer each time as that was the point of a docking station was a single connection. Any suggestion on what I can change to get this to work correctly?

With the HDMI monitor connected to the docking station and the docking station connected to the computer, go to control panel > sound > playback device tab and select the monitor to be your default playback device and your default communication device by right clicking the instance and setting the check marks.

did you get it working that way? i am having the same problem with a philips monitor…