Just to add my 2 cents,
Older games that supported MT-32, did so because that's what the music was developed on. The games usually contained completely separate adlib/soundblaster (OPL-2) tracks, and later games had a generic "General Midi" driver.
Why did they offer Adlib *and* MIDI as an option? Were there soundcards that only supported MIDI?
So getting a "real MIDI" synth with dosbox is kinda going into hardware that the average person didn't have when they played these games.
Huh? There are numerous DOS games from the later era that *only* offer music via MIDI. Mad TV 2 and Daggerfall are two that come to mind right off the top of my head, I'm sure there were many more.
The Gravis Ultrasound (If you could ever get it to work back in the day) was the only wavetable sound card that forced adlib/soundblaster emulation through it's wavetable. If you had a real AWE32 or 64 (I did) when you played a dos game that expected an adlib or sound blaster, you got adlib/soundblaster OPL-2 music, not wavetable.
Given that I'm not suggesting emulating Adlib through MIDI, I'm not sure what this has to do with anything. 😀
So the only real target's are MT-32, General Midi (and use an external synth independent of DosBox), or Adlib emulation.
Adlib is already emulated. Why must general MIDI be through an external synth? And as for MT-32 (which by the way is just another MIDI synth, albeit a famous one)...
If someone wanted to actually make a legal MT-32 romset without using any of Roland's material, they could very well do so, but that's also outside the scope of dosbox, and I wouldn't expect it.
Why? It seems to fit very comfortably inside the scope of DOSBox to me; PC speaker, GUS, SoundBlaster, and Adlib (OPL) cards are already emulated. What's so different about MIDI?
One of the advantages ScummVM has is that it emulates the virtualmachines of the game, and can remap the play music functions, this can include remapping the sound to play a FLAC/OGG of what the music is supposed to sound like, and thus never having to worry about emulating a synth.
Well yeah. That's obviously totally different because they can focus on getting a few specific games exactly right rather than being a general-purpose emulator.
By the way, it looks like there was a project to do just that, and integrate MT-32 emulation into DOSBox here, but for some reason it was abandoned years ago. Perhaps the code there could be picked up? I'm not demanding this now or anything, just asking why it shouldn't be a long-term goal. 😉