I never really bothered to have sound within QEMU. But just today I wanted to test something in the new image , and I finally decided to look for the switches necessary to do so. It is actually trivial, with some caveats. This is what I run
qemu --enable-kvm -m 4096 -soundhw hda lombix-2019.img
That emulates the HDA codec that I have in my desktop, and with that I can try to sort out some minor issues with the snd-hda-intel module.