Looking at the
manual, your BD player has only HDMI connector, you cannot connect RCA (red/white) soundbar directly to it.
If you have connected the soundbar to the TV, it passwes unprotected signal source to the RCA audio output, but not "protected" signal from BD player.
You might try a device called
HDMI audio extractor, but there is not guarantee it will work with BD players, and all movies you watch.