I have the exact same monitor as this guy and I have almost the same question. Here is my situation. I have my Monitor connected to my laptop through HDMI. The monitor has speakers built in and the sound over HDMI is working fine. Just recently I bought some speakers and a receiver. My monitor has a SPDIF out and I connect that to the coaxial digital input of the receiver. So here is how it is. Laptop to Monitor via HDMI then Monitor to Receiver Via SPDIF. The issue I am having is that the sound is not even coming through my receiver. I looked into the Realtek Audio Manager and my default device is HDMI output.