@Jbs - Oh good catch, for some reason I thought these were preamp outs.
OP: If this is coming from a modern TV, why not go from the TV to the sound bar directly?
RCA to Optical Converter
I have an older Onkyo TX-8050 receiver. I want to connect the speaker output (left & right, each with a red & white RCA female connector, total of 4) to my Bose soundbar. The only option I have for input on the soundbar is an optical female. How do I do this?