@gerwin,
I am testing a daughterboard which is identical to the one featured in your original post; 2nd photo - the Korg "XTOP 005".
I think mine may be defective. It is mounted on an 8-bit Roland MPU-401 card. I have a 16-bit SoundBlaster in the next ISA slot on the mobo. The MSEL jumper on this SoundBlaster has been opened, to set this card's MPU port to 300. The Roland card is operating on the 330 port address, which I think it is "hard-wired" to do.
The problem is that some (not all, but some) of the sound coming from the Korg's midi output sounds muffled. It's a bit like playing a very old cassette, when you hear muffled poor quality sound, with cassette-like "drop outs". But, and this is interesting, this poor sound quality only occurs on approximately one of the midi music "tracks". Most of the music seems to play "cleanly/correctly". But there seems to be one "track" that plays poorly. It sounds like either the drum/percussion, or perhaps some kind of "special sound effects" "track".
I swapped out this Korg DB for a Roland SCB-55 DB, and reran my test game: Descent 2, level 2. This sounded fine, no problems at all. So, with this basic test done, it seems there may be a fault with the Korg daughterboard's ability to play *all* the midi song's tracks cleanly/correctly.
Any thoughts please? Thanks a lot. 😀
Edit: I wonder if this extra info might be useful - The MPU-401 win98 driver was the default driver from the win98 CD. My test game, "Descent 2", was run from windows 98 as it uses DirectX 2.
Edit 2 (solved) I seem to have answered my own question. I removed both the Roland MPU-401 card, and it's associated windows 98 driver, and mounted the Korg DB on the SoundBlaster card. I re-ran the Descent 2 test, and the midi music sounds fine. Perhaps the default win98 MPU driver is not functioning correctly?