When I install one of the 90-day Windows 7 trial VMs for Virtualbox on an Ubuntu 16.04 host, everything works fine except sound. The Device Manager shows an unknown audio device, but can't find any driver for it. I'm not sure how to proceed, as I haven't had to deal with hunting down Windows drivers in a long time, and even then, I'm not sure what driver I'm looking for. A Windows driver for a virtual audio device to Linux? Would it be the driver for the physical audio device on the host?
Googling this problem is nearly impossible since a large combination of host/guest/sound issues come up for the same search terms.