Had the same problem. It's a mess up with the slingbox programming. If you are using the HD signal and the component cables you must use a digital audio cable (single cable, usually orange). If you have to use the composite cables for the audio (2 cables usually red and white) then you have to use the same cable for the vidoe (usually yellow). Essentially if you don't have a digital audio out on your hd box then you can't get hd from the slingbox and get audio. To test this, hook up the red and white audio and the hd picture component cables. Under setup see if you have a picture with the component cables and no video, then select composite and see if you have sound but no video. I hope you have a digital audio out on your box.
Thanks. That explains the problem.
To confirm, Slingbox setup requires either all analog video and audio
HD video and digital audio
no combination of the two. (I wish they explained that anywhere in their documentation!)
I DO have an digital audio out on the box, but it is optical, while Slingbox digital audio input isn't. So I will have to connect an optical cable, plus a converter to a digital cable to test.
There are two sets of analog audio inputs,. One for HD w/component video inputs (RGB), one for SD w/composite (yellow). Use the set nearest the composite video inputs (seperated from the component video inputs by the digital audio connector). Use the corresponding output audio jacks.
I have the SlingBox ProHD, this works for my setup.
I also ran into the same problem. What I figured out was that in the Web setup you do not have the option of audio inputs. If you download the slingplayer application, and run the setup you can configure which of the audio ports you want to use. Mine was obviously set to the digital and I changed it to analog.
You can definately run the HDMI at the same time. Strange that they would not include this in the web setup.
Also you can configure the volume, I had the slingbox classic and the audio was way louder. I could not figure out why, but when I looked at the setup with the separate app, I was able to configure that too.
Hope that helps.