Aurora-R7, no audio through any audio ports

I have my r7 connected to a tv through hdmi at the moment. sound works fine if i select the TV as audio output. if i try to connect my external speakers to any of the back or front ports and select  'realtek Audio' in windows 10 i don't hear anything. I have all the latest drivers installed from the dell website.

i have read online that connecting through hdmi straight from the graphics card might disable the onboard sound and it might have to be manually turned on in the bios again. I had a look at the latest alienware bios but there wasn't any sound options?! 

any ideas on how to fix this?

I apologise for all the run-on sentences ha