I have MT-32 setup and working in DOSBox but I don't know how to get it working in the OS X installed version of WC I+II. Is there a config file I need to change in the package to get it going?

OK, so after some digging I found the answer.

1. Right-click on the Wing Commander icon and show package contents.
2. Navigate to Contents > Resources
3. Right-click Wing Commander.boxer and show package contents
4. Open the "C WC.harddisk" folder
5. Open WINGCMDR.CFG in a text editor
6. Replace "v a904" with "v r c27"
7. Save and enjoy (assuming you already have the MT-32 ROMs).

WOOO! Thank you SO much for this. Works wonderfully (as far as I've tested)...although doing the same process on WC2 only works until the first speech, and then it crashes.

That's unfortunate. I have no issues in WC2. Could you have a typo? Maybe the line ending changed? Though that last one shouldn't be an issue usually I have run into that before on rare occasions going back-forth between windows and Mac. Double check the line ending is CRLF (DOS) and not LF or CR.

Let's see... the original wc2.cfg file reads:

v a904 c25 d1

Changing that to read:

v r c27 d1

leads to the MT-32 working fine, and the opening speech gets through two words before it cuts off, and the game becomes unresponsive. Any ideas?

Ah, there's the problem. Put c25 back. Apparently that's for the SB which plays voice files. The WC2.CFG file should read:

"v r c27 c25 d1"

I was sure I had tried that permutation, and had the same issue...but as soon as I copied and pasted your line, of COURSE it worked perfectly. Thanks again...I thought I had left behind the days of messing with Sound Blaster settings two decades ago!

An easier way might be to download Boxer (which is what the GOG wrapper for the OSX version of the game is based on), and set it to use the MT-32. According to Boxer's author, that should also allow GOG games to use the MT-32. I've done this and I'm pretty sure I'm hearing MT-32 sound in WC, without touching WINGCMDR.CFG.

Thank you very much. I just got MUNT running and was looking for these values. There's only one problem: applying these changes deactivates the newly added Secret Missions 1.

Edit:
Found the solution two seconds later. :P
The line for both Roland and the addon is:
"v r c27 z"

Apparently the "z" tells the game whether Secret Missions 1 is installed and allows it to be run from the main menu. Secret Missions 2 and the addons for WC2 don't seem to need any special care since they are run through separate executables.