Documentation for how sys-audio communicates with speakers?

I’m suspecting that something about my built-in hardware speakers in my laptop are not functioning well with sys-audio. Sys-audio will not send sound to them after running my laptop for too long. I haven’t found any documentation that explains how sys-audio gets a hold of the hardware control of the speakers. Does this go through dom0? Is there direct access? What program are they using? If anyone knows where to look let me know.