you can actually see the signal on the optical spdif if it's working like this one around 1'20"
https://www.youtube.com/watch?v=6fcLsuGQlx8
if you are not getting this signal, there's a problem with your source... go into configs and make sure you turn it on... xbox right? should be settings in there to enable optical out. that's the likely culprit.
also on the soundbar, i'm sure it's obvious, but there's probably a toggle for the input selector... just checking
