So I Have an ASUS Maximus Hero IX Z270 chipset. So it goes without saying the motherboard has capability of 5.1 surround sound. My surround sound is the SOnly Home Theatre System BDV-E2100 and it has an optical audio port. I am using optical cable and plugging it directly from the spdif port on the motherboard straight to the optical port on the Sony reciever. I go into windows sound scroll down to Realtek Digital Output and the configure option is greyed out so no luck fixing it through there. I right click the Realtek digital output and do properties click on advanced and default format says only a series of 2 channel formats is available. So that leads me to the Realtek audio manager gui shows Speakers (my headphones) with a TON of options like setting up virtual surround and all sorts of settings. But I click on Digital Output and bam the only settings I can set is Default Format between a series of CD formats and DVD formats, and thats it. So hours of research have led me to no avail. Also not the surround sound system is brand new so there are no faults with that. So my question is how can I get it to detect 5.1 surround sound?