I got the sound to work like this:
Install Dune in LaunchBox as normal by only installing to hard drive. DO NOT DO AUTOMATIC CONFIGURATION! Before the next step which is to find the startup file go to the Dune.bat file and edit it like this:
@echo off
logo
SET BLASTER=A220 I7 D1 H5 T6
duneprg ENG VGA SDB2227 EMS 386
Save the file (overwrite)
Next go back to LaunchBox and when asking for the startup file (it will default to DUNEPRG.EXE, change that to Dune.bat
Finish that wizard and TADA, you will have sound!!