Have a sony blu-ray connected via component/audio to my Pioneer media center, which outputs Optical audio to my Demon receiver. Works fine. I decided to switch the component/audio cables between the blu-ray and the Pioneer with a HDMI cable. But for some reason, the audio gets to the Pioneer and goes to the Pioneer Plasma's speakers, but does not go thru the optical cable to the Demon. I did the same thing between my tv cable box Scientific Atlanta and my Pioneer (PDP ARO5U), that is switching the component/audio cables for a HDMI, with the same results: the audio will play thru to the Plasma, but does not go thru the Optical cable to the Demon receiver. My apple TV connected via component/audio continues to go thru the optical cable to the Demon. I know the audio is getting to the Pioneer media center, as it sends it to the Plasma speakers; and I know the Pioneer sends audio thru the optical cable, but only audio connected in any input except the HDMI inputs. Any suggestions before I give up and throw the HDMI cables away and go back to the component/audio cables? Thanks for any help.

By component/audio did you mean analog audio? There is no such thing as component/audio.

Because of HDCP I don't believe that HDMI allows audio to be outputted through S/PDIF (optical or coaxial). You need to connect your receiver by HDMI also.

Probably means either composite AV or component video with analog L/R audio.

I believe William is correct with the HDCP issue. Kinda sucks.

Thanks for the info. My Pioneer media center does not have hdmi out, so I am guess I am stuck using component. Thanks again.

Thanks for the info. My Pioneer media center does not have hdmi out, so I am guess I am stuck using component. Thanks again.What's a Pioneer media center and why can't you just connect the source to the Denon receiver directly via HDMI?

My Pioneer Plasma comes with a monitor and a media center, which is where all the connections are made. The monitor only connects to the media center. Most TV's have all their inputs and outputs on the TV; with mine all the inputs and outputs and on a separate component, which has a special cable connecting to the monitor.
My Denon is older with no HDMI connections. But today I am going to go shopping for a new Denon (Circuit City still has some) that has HDMI, and then I can do as you suggest: the blu-ray and cable box connect directly to the new Denon with HDMI, and then the Denon connect to the Pioneer media center with HDMI. I really like the quality that HDMI brings.