now one problem with current is that one thing gets improved and may throw something else out.
In terms of fixing your issue there are two approaches:
1) read up on modprobe and all other tools to see if module for said sound hardware loaded etc etc In fact have you done that and you know either module is not there or not being loaded ?
when you say you updated the kernel what about everything else?
2) Since Patrick V seems to be on a roll and i see from change logs that kernel is now 5.4.14 maybe re-visit on doing an upgrade. The upgrade migth just fix your issue.
(I installed stable 14.2 and it couldn't see nor use my wifi card. I decided to go for current and that fixed it when i installed Sept release of current )
I installed "current" in Sept 2019 and upgraded about a week or so back; i went through my experience of doing an upgrade of system (including kernels) using slackpkg here:
Good- I'll see if Slackware 15 is out yet-- i mean better than an older current version. 15 is not released yet. But you can upgrade one old version of current to a newer one. That what i did i upgraded from September release to yesterday which changed kernel 4.19.75 to 5.4.12 along with...
have a look through that then to read original article by "Alien Bob" go to slackware docs: