I have looked into a problem with Turtle Beach Multisound Classic DOS support. There are actually two problems: one with PRESETS utility loading drum presets incorrectly, the other with AIL driver (MULTISND.ADV) playing drum presets incorrectly (even if they are correctly loaded).

The first one may be circumvented by loading presets by Windows 3.1 drivers. The other seemingly can't be circumvented. Although Windows Media Player plays MIDI files correctly, anything using multisnd.adv - be that PX player or MIDPAK's setm.exe would play with drum presets partially out of place.

Digging deeper and deeper, I came to conclusion that Proteus 1/XR has several drum sets with different key-to-patch maps, but none of them have GM compatible maps. While Proteus presets 0-127 are modified with SYSEX messages, there is no mechanism to renumber drum keys within the drum preset in Proteus, so this should be tackled on a driver, not hardware level. For some inexplicable reason no version of MULTISND.ADV driver takes this matter into attention. However, Windows 3.1 Multisound MIDI driver seemingly does, judging by correct playback result.

I built an Excel file and crudely remapped GM drums to Proteus 1/XR:

And modified the driver:

1DRUM_REMAP  db 35 dup (0), 52, 36, 55, 38, 39 
2				db 53, 40, 42, 43, 44, 45, 56, 41, 47, 49
3				db 84, 50, 49, 0, 78, 86, 94, 49, 39, 50
4				db 65, 64, 65, 64, 62, 96, 95, 82, 58, 104
5				db 66, 0, 0, 108, 107, 63, 61, 61, 0, 0
6				db 0, 0, 46 dup (0)

1				xor cx, cx
2				mov cl, DRUM_REMAP[si]     ; replace GM key number with corresponding Proteus 1/XR key number
3				mov si, cx 

And bingo - it works. My drum key conversion is far from perfect; however, MIDI songs now sound more or less correctly. Modified AIL driver is attached.

List of DOS games supporting TB Multisound Classic: here.

Problem with loading presets in DOS is yet to be solved, until then Windows drivers should be used to load GM presets to Multisound Classic.

If someone has suggestions about remapping, here's the link to Google Spreadsheets. Modify it and say here about your modifications, so that I review them and rebuild the driver.

Speaking of the playback quality, despite Proteus 1 never supported General MIDI and was just adapted to play General MIDI tracks using Proteus SYSEX controls, it really destroys most of the General MIDI soundcards and daughterboards. Add nearly noiseless DA converters (shame on you AWE32!) and there's Turtle Beach Multisound.