I hate to necropost an old thread: Freddy Pharkas Frontier Pharmacist CD

but just anyone comes across it searching for a solution (like I did):

I found that by changing the SBTYPE to SBPRO1 in the .conf file, this solved the sound problems I was having with Freddy Pharkas CD-ROM. No need to fiddle with drivers from different sierra games; just change this setting and it worked out of the box.

Now that the games are available via GOG and running well in SCUMMVM there's less interest in getting it running in DOSBox, but if you're like me and trying to re-create the original experience, here's the solution. No more crackly sound or too-fast speech.

DOS Box v0.74, BTW.