I read your post and installed Wing Commander on my Pentium 75 with MS-DOS 6.22. When I try to run it, it locks after "Expanded Memory Detected" is displayed on screen. Is it the same problem as you have? But Adlib-music works fine. I have a first generation MT-32 without the headphone jack and it's connected to the gameport of a ESS Audiodrive soundcard.

Do you see anything on the MT-32's display while the computer is locked up?

Do other games work with the MT-32 using that hardware setup?

Most games work on my computer with the MT-32, except for these:

Simon the Sorcerer 1
Waxworks
Battle Arena: Toshinden
Eric the Unready (But it's because it needs MPU-401 intelligent mode)
Wing Commander

Nothing is shown on the display of the MT-32 when I try to start any of these games. And they all run well if i select Adlib-music. I've tried replacing my ESS Audiodrive with two different Soundblaster 16 PnP, but the problem persists.

The MT-32 has lots of issues if the MIDI interface on the card isn't a true MIDI interface (as with most of the >Soundblaster Pro line as well as, I believe, the AudioDrive).

For older Sierra titles, there's a fix available in the MT-32 Resource Center at queststudios.com, for other titles... I'm not sure of a way to fix them unless they use 'drivers' of some form or another, like the Sierra titles.

Also make sure that you have both the MIDI-Out and MIDI-In working, since the application may be waiting for a response from the MT-32 (though that is somewhat unlikely).