I'm actually playing the Steam release right now, but dosbox is still relevant to JA1.

It seems to be loading yet it sounds like adlib.

"CONFIG:Loading primary settings from config file dosbox.conf
MIDI:win32 selected MT-32 Synth Emulator
MT32: Using 10 chunks, chunk size: 480 frames, buffer size: 4800 frames.
MIDI:Opened device:win32
DOSBox switched to max cycles, because of the setting: cycles=auto. If the game runs too fast try a fixed cycles amount in DOSBox's options."

Can anyone help me out here?

Also how can you tell which version of JA 1 you're running and what was the last version released for it?

I seem to have had it working at some time, but I have switched systems and no longer have a fully capable dosbox. The only thing I can think of is that you didn't mention having run SETSOUND yet. If you were running the default gog install, that would be hard to miss, since it's one of the startup menu options, but with the Steam version, who knows? Easy enough to just run by hand, though.

I am using the GOG version with MT32 music without any problem. I'm using my own install of dosbox, not the one provided with the game, and I have Munt installed separately. Works like a charm.

I haven't tested the steam version, but the GOG version is 1.13, and not 1.13b. Applying the 1.13b solves an audio issue with the SB16 driver. So I recommend applying that patch if the steam version is the 1.13 too. The game's version is displayed when the game starts, it should be 1.13b (Sep 07 95) and not 1.13 (Sep 05 95).

I see set sound in the Installed/JAGGED folder but have no clue how to run it.

How would I run it by hand? Where can I find the 1.13b patch download?