If the computer's audio isn't coming out from the room speakers, follow the instructions below to check the configuration of the PC. (Click on the images to enlarge them)
1. Right-click on the speaker icon in the lower right tool bar.
2. Left-click on 'Playback Devices'.
3. Right-click on 'Speaker/Headphone', then left-click on 'Test.'
4. You should see a green audio level on the right side of the window corresponding with the selected output.
If the system audio is being fed to the 'PC Speakers / Headphones' output, you will hear audio from the room sound system. There should be a green check next to the Speaker/Headphone icon to show they are set as default. If no audio is heard, continue to the next step.
5. Right-click on the digital audio entry, (either “HDMI” or “Crestron 420”), and then left-click on 'Enable'.
If the 'Enable' option is grayed-out, this selection is already enabled. 
6. Right-click on the digital audio source, either “HDMI” or "Crestron 420”, and then left-click on 'Test'.
7. You should see a green audio level on the right-hand side of the window.
If the system audio is being fed from the PC HDMI cable you will hear audio in the room sound system. 
8. Right-click the digital audio entry, either “HDMI” or "Crestron 420”, and then left-click on 'Set as Default' 
