Games have their own specific implementations of their instruments in DOS, while Windows drivers use some sort of one-size-fits-all arrangement which may not always sound all that good for any given MIDI file.

If i use Adlib (Real OPL3 in real DOS) in Duke3D the duke Theme in the Setup and the one in the Menue sound different.
And i am not really sure why. Maybe the playback of the file uses different routines in the setup and in the game?

Also in windows you can select the playback device for midi in the settings. Maybe you are using the integrated MS synth instead of the OPL synth from the card...

I assume dos is probably using opl while windows is using its midi stuff in this case. Just a guess though.

SEAL2 has a *.MID player application, maybe it's worth a try. The actual music is being made by Allegro library, though.
OPL2, OPL3 and EMU 8000 are among the sound devices supported.

Edit: In Windows, there's an OPL3 emulator driver available. It may sound similar to OPL3 in Windows 3.1 using the Creative driver.
https://github.com/datajake1999/OPL3EMU

Back in the day, I preferred the Voyetra Super Sapi driver, though. It was part of my PAS16 disk set.

As Tiido mentioned, DOS games have their own MIDI implementations for the OPL2/3 FM synth while Windows uses a generic one that it may not be ideal for everything. It is also likely that the device used for listening MIDI files with WMP or any other Windows software isn't using the FM synth.

P.S. Try to run both Duke Nukem 3D and Descent within Windows and you will see that the music will sound exactly the same as running it directly in DOS. 😉

DerBaum wrote on 2024-01-13, 16:43:

If i use Adlib (Real OPL3 in real DOS) in Duke3D the duke Theme in the Setup and the one in the Menue sound different.
And i am not really sure why. Maybe the playback of the file uses different routines in the setup and in the game?

Yes, the Setup util uses different instruments compared to the game itself, it is why it sounds different.

Tiido wrote on 2024-01-13, 19:53:

DerBaum wrote on 2024-01-13, 16:43:

If i use Adlib (Real OPL3 in real DOS) in Duke3D the duke Theme in the Setup and the one in the Menue sound different.
And i am not really sure why. Maybe the playback of the file uses different routines in the setup and in the game?

Yes, the Setup util uses different instruments compared to the game itself, it is why it sounds different.

thanks.
good to know. i want to make sound recordings and want to have consistent and reproducable results.
it really confused me why some recordings i listend to on youtube sound good and other ones sound like crap...

Conclusion: I will always record the real game and not use a midi player. 👍

DerBaum wrote on 2024-01-13, 19:57:

Conclusion: I will always record the real game and not use a midi player. 👍

At the moment i research how games use / set up the FM chip for playback.
I came across this thread : What games contained OPL instrument patches for all General MIDI instruments?
wich was quite informative.
Games can set the instruments of the FM chip and the Drum sounds in different ways.

Maybe a player esists that can play songs from games and load a specific set of instruments for the FM chip (either automatically if the fileformat allows it, or manually).

This is a super interesting topic to investigate further.

DerBaum wrote on 2024-01-18, 04:59:

Maybe a player esists that can play songs from games and load a specific set of instruments for the FM chip (either automatically if the fileformat allows it, or manually).

You can playback VGM files with a player that support hardware OPL2/3. VGM files contains the recordings of instructions that are sent to the synthesizer chip.

VGMRips is a source for VGM files and players.