Brother, you completely missed the point. What I'm complaining about is that GOG chose to configure Pagan with Adlib Midi instead of SB music, when DOSBox has the capability to capture all video and audio from gameplay EXCEPT any midi music. The music per se is similar with AdLib and SB (it's NOT the same as you appear to believe), but this is not my rant.
Ok maybe I completely miss the point, because frankly I am not anymore sure at all what you mean. :) Maybe I should check what are the music options in Ultima 8, but I think I originally tried it also with Adlib and SB music options, and didn't hear any difference.
Unless there was a separate music (not effects) option for Sound Blaster 16 or Adlib Gold (which offered a slightly better OPL3 synthesis, which to my recollection was never really supported widely in PC games due to General MIDI, ie. you'd normally get OPL2 music with those cards too), the "Soundblaster" option in U8 most probably sounds identical to Adlib, because Soundblaster 1.0, 1.5 and 2.0 used the very same Yamaha YM3812 chip (OPL2 FM synthesis) as the original Adlib sound card. Soundblaster Pro and Pro2 had two similar OPL2 chips, offering "stereo" sound, if any game would support "stereo" sounds for FM music.
EDIT: Unless you mean that DOSBox itself would somehow yield different kind of music whether you select Adlib or Soundblaster for Yamaha OPL2 music, but I don't know why and how they'd do that. Maybe I'll have to take your word for it for now, but it interests me enough so I think I need to try it myself, as I used to be quite keen on PC gaming music back in the early 90s (MT-32, SCC-1, SB16, GUS etc.).
As long as you're using DOSBox, I don't think sound card specs really matter, since all sound is emulated by DOSBox. And since you apparently like the Pagan MIDI music better, you're free to use it, I'm just asking for an option.
By default, I don't think DOSBox tries to emulate the soundbanks of any (General) MIDI or MT--32 compatible cards.
I think DOSBox simply passes any MIDI (General MIDI, or MT-32/CM-32L) MIDI messages to any MIDI device that you have configured in Windows. By default, that device in Windows (XP/7) is "Microsoft GS Wavetable Synth", which gives passable, but still pretty poor, General MIDI sounds.
You can enhance that quite a bit by installing in Windows e.g. BASSMIDI drivers/utility and using some other, better, GM/GS/XG soundfont (and telling Windows to pass the MIDI messages to BASSMIDI, not "MS GS WT Synth"), or even using a real General MIDI card or module to which you pass the MIDI messages coming from DOSBox.
That's also how you achieve Roland MT-32/CM-32L music from DOSBox games: you install a MT-32 Synth Emulator, and associated files (like the proprietary Roland MT-32/CM-32L ROMs containing the actual instrument sounds) into Windows, and tell Windows to pass any MIDI messages to that MT-32 emulator (driver). DOSBox just blindly passes those MIDI messages from the DOS game to the Windows MIDI device, not knowing at all what MIDI messages they are (General MIDI, GS, MT-32, whatever).