I know this isn't as elegant as the "official" version, but to me it worked.
I can't post to the apropriote forum, move or delete as you find suitable.

1.) Get the SB update drivers from the official website.

it's called SB2UP.exe

The website will say you also need the original drivers.

2.) unpack to a directory (in modern terms: folder)

3.) run dosbox, start windows.
4.) In control panel, goto "drivers"
5.) Install the Soundblaster 1.5 driver shipped with windows diskettes.
6.) configure to 220/7 or whatever you find apropriate
7.) restart windows, goto drivers again, select "updated or unlisted drivers"
8.) select the directory with the unpacked sb2up.exe
9.) install all three offered drivers (soundblaster, audio, and something about FM synth)
10.) config em
11.) restart and hear the sound.

actual menu names may differ since I used a German version.