Need help with no audio on Chromebox with dual boot to Ubuntu

I'm a noob to Linux and this is my first attempt at doing this. I have an HP Chromebox and have it dual booted to Ubuntu. I can't get audio to play with streaming from the internet, such as popcorn time, pandora, youtube. I can play video and audio from files on usb drives and the test sound function works. It is set up with HDMI>TV>Optical>Sound Bar. The sound works fine in Chrome OS.

ETA: I can hear youtube videos through firefox, just not through chrome browser.