After discovering that I could use them for System Shock to make the music sound better, I wanted to test BASSMIDI with a GOG release like Might and Magic 3. So I changed "midiconfig=" to "midiconfig=0" in the config file and made sure that I'm was using Port A of the BASSMIDI driver. Unfortunately, I haven't noticed any difference. I even checked using "mixer /listmidi" and it does appear that Port A is set to 0.

In case you're wondering, I have the soundfonts listed in this order in BASSMIDI:

CrisisGeneralMidi3.01
Arachno Sound Font - Version 1.0

I found that Arachno gave the best results for System Shock, but it's a shame I can't seem to make things work with anything from GOG at the moment.

Update: Okay, I figured out why things weren't working out. It's so simple and stupid I could almost cry. I didn't realise that all of the changes I made to the config file only affected the game's shortcut in the program folder, not the desktop shortcut which I kept using. By the way, I've also discovered MUNT, but I'm not sure if that works without going through the installer and choosing the Roland sound option (Launch Settings shortcut).

I used a soundfont for Betrayal at Krondor, but I'm by no means an expert. I simply followed the instructions in this thread:

http://www.gog.com/forum/krondor_series/guide_to_betrayal_at_krondor_music_and_sound_effects_settings

Perhaps these would help you get it working with the Might and Magic series too?

If you are using Windows 8, this is what you need to install:

http://coolsoft.altervista.org/en/virtualmidisynth

Works with all of your midi supporting games. Automatically!