A little google research turned out that your devices soundcard is not well supported in Linux: https://bugzilla.kernel.org/show_bug.cgi?id=95681
There are, however some people reporting various success by following the instructions there. But be warned,the Thread is huge and not every instruction there is followable on Endless, especially not those with patches for the kernel.
TL;DR
Try the following commands and see if you can get some audio output: