What!!?

[JonnyCam]

I can adjust the volume fine. The reciever really is the main volume control I use, but I can use the Hauppage remote to reduce input volume when needed.

You shouldn't be able to do that, as it's a digital conection, and there should be no volume control between the digital stream & the output.

However, if you are using something like AC3filter, then you could adjust gains etc and that would prob affect the spdif output (as long as it's not an AC3 track, in which case it should pass it through direct)