Originally Posted by mbennett674
Don't know why I didn't do this in the first place, but connected HDMI to Receiver and then disconnected TV and Audio worked fine. It must have something to do with HDCP. Anyway - now running video through HDMI and Audio through Optical....
The source device, in this case your cable box, is required to set up copy protection through all the interverning devices all the way to the final device, in this case your display. Some of these cable boxes don't actually implement that and thus only work if their HDMI is directly connected to the display. Yours apparently doesn't have that problem.
But some of these devices have ANOTHER problem, which is that they incorrectly assume the display will handle HDMI audio even if there is a receiver in the middle. In your case that would mean the cable box would mute the HDMI audio when your DVI display is connected and powered on because a DVI display can't receive audio over that DVI connection. With no DVI display connected, the cable box sees just the receiver and determines that the receiver can handle HDMI audio.
This would be a bug in the cable box. In the course of setting up the connection the cable box should learn that the receiver will accept HDMI audio and should keep the HDMI audio going despite the fact that a DVI display is on the other side of the receiver.
Alternatively, it could be a bug in the receiver which is sending the wrong information to the cable box. When the cable box interrogates the receiver as to whether it will accept HDMI audio, if the receiver says NO because there is a DVI display connected to its output then that would be a bug in the receiver.
You can figure out whether it is the cable box (likely) or the receiver (unlikely) that's at fault here by trying a different HDMI source device, perhaps an HDMI DVD player, and/or trying a different model of HDMI receiver.
EDITED TO ADD: Some receivers have a setting that adjusts whether HDMI is simply passed through (audio not extracted) when there is a display connected to their HDMI output. Look for that in your receiver and if you find it, turn it off. That may make the receiver accept the HDMI audio even when your DVI display is attached. This is unlikely to be your problem since your HDMI audio is working when you disconnect the DVI display, but check for it anyway.