No sound via Optical Output

Hi First post here goes!!! I have a Western Digital HD Media Player running firmware 1.06.15 software and I cannot get any sound via the optical! I connected the Western Digital to an ONKYO TX-NR609 AV via the HDMI and Optical cables. In the Western Digital sound options I have selected sound via optical and there are four options I.e. DTS etc not certain which option I should select. I certain the ONKYO 609 can do Dolby !!! I have also altered the options on the ONKYO and done a firmware update on amp altered setting on input cable to optical but still no sound is passed through. If I alter the options on the WD for sound via the HDMI sound works fine! What am I doing wrong??? Many thanks Al

It’s possible you need to set your ONKYO to “receive” the audio on the OPTICAL while receiving the video on HDMI.

I know I need to do this with both of my Pioneer AVRs;   by default, they expect the Audio to arrive on the HDMI cable instead of Optical.

In reality, you would probably want to do HDMI anyway if it’s available to you, right?  Not sure why you’d want to use optical.