To play MIDI in OPL3 through DosBox, you need an actual DOS program that is able to play MIDI through the OPL3 chip.In my case, I used the original Setup.exe that comes with Descent.I selected OPL3 as music hardware on it, and used the Test Music option, that starts to play Level 12 song by default.Then what I did was to replace the Level 12 song MIDI and FM bank files each time I wanted to record a song with the desired level MIDI & Bank files, then put Test Music on the Setup program, and then record all DosBox audio output through the Stereo Mix input of my sound card and any sound recording program (Cool Edit Pro in my case).
Have you tried DescentiaPedia: Game Audio Player?
Iron Ian, I haven't gotten an opportunity to relish in your findings much, but I'm just curious; I have this long-standing theory that EVERY Descent 1 and 2 MIDI is a correlation of a Descent 1 and 2 Rebook Audio song. Now, some are very obvious like, Game02 and Virtual Tension, or Game18 and Hydraulic Pressure, but in your findings and your connections with a lot of the music artists, have you found this to be true with all of them?