I've been trying the method mentioned in the GOG wiki in which you install Munt. I got the 64-bit version and installed it. The readme says I need the mt32emu.dll and mt32emu.inf files in the same directory as the roms. The problem is that I cannot find those files. I managed to find mt32emu.dll after searching around, but mt32emu.inf doesn't seem to be anywhere on my system.

Is it supposed to be on your system? Judging by the filename it sounds like a file that should be included in the Munt package.

The installer does install those files. Whether because of it or Windows 7, the .dll file ends up in a folder in the Windows folder, and the .inf file doesn't seem to exist at all. Do you perhaps know where I could find those files loose?

Even is the installer is an exe file you'll probably be able to extract the file manually, if using a program like Universal Extractor.

I used 7-zip to extract the installer, and while there was a mt32emu.dll file, there was no mt32emu.inf file.

Anyone know of an alternate link to the 64-bit installer?

Look at my post: http://www.gog.com/en/forum/ultima_series/how_to_get_the_most_out_of_ultima_underworld_2

Roland Virtual Sound Canvas emulator is much nicer, better then Munt, imho.
(It doesnt need Roms.)

but how to apply the fan made
- General MIDI Patch V1.1
or
- Ultima Underworld - The Stygian Abyss
Midi music for the Roland Soundcanvas

or are they pre-installed with Gog version?

You can add the general MIDI patch to the GOG version using Ultima Patcher. This can also apply various fixes for the other Ultima games.

Thanx, that Ultimate Gog ver. patcher dealt nicely with one General Midi pather (namely Ultima Underworld: The Stygian
Abyss General MIDI Patch V1.1 by SkyGracer aka Panzer Dragon (UDIC).)

But not with this one, I found somewhere, which is really much nicer with Sound Canvas emulation:
https://dl.dropboxusercontent.com/u/12413456/UUWmidiRolandSoundCanvas.zip

(I copied it to Data folder, no success. Could listen to it though via the emulator's player)

Any videoes on YouTube of Ultima Underworld using the Sound Canvas emulation? I'm most interested in the sound effect differences, the music I usually turn off in single character first person view games.

I don't think you can simply copy MIDI files in and have Ultima Underworld recognise them; its own music is in XMI format which is not the same thing.

Either way you can't override data files by simply putting them in those folders unless they already exist there; you'll need to replace them in the CD image by building a replacement image.