I can cast music to my Sony Bravia XBR 65x850b tv.
However when I have it as a a duplicate display sound I get on the speakers primary display does not come from the speakers on the TV.

On the device manager the TV shows as a media device.
However, the TV does not appear under sound.
Alll that shows under sound is
Digital audio (S/PDIF). Digital audio is set as default

How can I have any sound on my PC desktop also come through my TV?

Do I disconnect my Speakers and have the sound come through my Samsung monitor?

What additional info might the list need to help solve this?