For my old HW collection, I am gradually 'upgrading' to BusterDog and Bullseye since StretchDog is getting less maintenance nowadays.
I am working on an old Fujitsu Lifebook S series (CoreDuo 1.83GHz, 2GB RAM).
No sound in BusterDog and Bullseye, but no such issue in StretchDog (sound working fine). I can hear the speakers making noise as if it was being initialized but failed.
Most of my installations are frugal install, so I reboot to Stretch/Buster/Bullseye depending on what I need.
I don't know AlsaMixer well. Just trying get troubleshooting pointers.
For starter, here's some details from Alsa...same in all 3 dogs.