Hi Miguel Orozco2,
Thank you for reaching Microsoft Community.
I would like to make sure first on the details of the concern and set up: you have a Surface connected to a dock then an external monitor connected from the Mini DisplayPort of the dock to an HDMI port of the monitor but not getting audio from the monitor. This works fine though if the external monitor is connected directly to the Mini DisplayPort of the Surface, correct?
- Can you please confirm on the model of the Surface, is this a Surface Studio 1 (Shop Surface Studio (1st gen) – Microsoft Surface) or another Surface mode? See this page for reference: Find out which Surface model you have - Microsoft Support.
- Also, which dock are you using? Is it a Surface Dock 1, Surface Dock 2 or a third-party docking station? See: Identify your Surface Dock and features - Microsoft Support for reference. If using a third-party docking station, please provide us with its make and model.
- What is the make model of the external monitor used?
For now, kindly try these steps below and see if this helps:
- While the monitor is connected to the dock, try to disconnect the dock from the Surface for 10 seconds then connect it again and ensure that they securely connected.
- Open Control Panel > Hardware and Sound > Sounds. Under the Playback tab, see if the monitor is listed. If not, do a right-click within the Playback tab then select Show disabled devices and Show disconnected devices. Once the monitor shows up on the list, right-click on it then select Set as default device.
If still the issue persists, kindly see this page and perform the steps suggested: Troubleshoot Surface sound and audio accessories - Microsoft Support
Let me know how it goes.
Kind regards,
Marrion