cannard: OK so what I've found out doing this requires actually having the MT-32 ROM files. Unfortunately they appear to be impossible to find unless you actually own a Roland MT-32 which I don't. So unless someone wants to *cough*PM*cough*me*links*cough* I'm just gonna say fuck this.
MIDI settings have unfortunately grown rather confusing in ScummVM, to the point where I no longer fully understand them, but as far as I know the patched EGA version will play the MT-32 tracks as well as it can if you use
Edit Game... from the launcher menu, and change the
Music Device on the
Audio tab to a MIDI-capable device. On Windows, the most common choice would probably be "Windows MIDI". If you don't hear anything, that may be Windows's volume settings. (Setting it to "AdLib", "PC Speaker Emulator" or "IBM PCjr Emulator" will cause it to play the old music, and therefore skip the overture.)
"FluidSynth" should work too, but is a bit more work. I need to specify a SoundFont file for it to use - I did that on the
MIDI tab of the
Options... dialog - and then you may have to play around with the
MIDI gain setting to get the right volume.
And of course, there's the MT32 emulator which, as you say, requires dumps of the MT-32 ROM files, and it should be possible to use a real MT-32 though I don't know how to do that at all.