So I have the 8300 HD Box and Im connecting to my Panny Plasma via HDMI. Now when I turn up or down the volume on the TimeWarner remote the graphic shows on the tv that im turning it up and down but nothing changes in sound.

When I turn the TV up with the TV remote, it turns up and down...Why is that? I dont have surround sound yet so just 8300-HDMI-Panasonic Plasma. Ive tried all the sound settings in the 8300 but nothing changes but when I do change to Dolby Digital I get no sound at all.

I forgot but I think the volume works if I component hooked up but I guess I need to test again.

Is it possible that you have to have the HDMI port turned on for audio in order for you to utilize the HDMI connection. It sounds suspicious that you would have to do that, but it's an option. It sounds to me like when you enable the DD, it disables the audio that is directed through HDMI and allow it only to feed to your coax/optical.

Is this the first time you have used that HDMI port on your television? Do you have another HDMI device you can try? To eliminate the television as being the culprit, I would try plugging something else in and checking for audio. As a last resort, no audio from any device would indicate the HDMI port on your television does not function properly or there is a menu item someplace to turn it on. Boy, turning it on sure sounds odd to me though.

You say that everything works just fine when connected through your component cables. That means that analog is working just fine, it's not working through digital however.

From what I've been told the 8300 has an older HDMI so if you want sound you either have to get a new DVR or run some cable just for sound.

I have the same box and the same problem :(