I managed to add Gravis Ultrasound support to System Shock 1 a couple of days back and tested it. Here's what I did:
Get Ultrasound drivers: http://www.dosgames.com/forum/about10574.html
Unzip it and use the ULTRASND411 file (Rename it to ULTRASND and put it in C:/)
Then, when inside the RES folder go to the dosbox.conf in either the dosbox folder or gulikoza and look for:
[gus]
#      gus: Enable the Gravis Ultrasound emulation.
#  gusrate: Sample rate of Ultrasound emulation.
#           Possible values: 22050, 44100, 48000, 32000, 16000, 11025, 8000, 49716.
#  gusbase: The IO base address of the Gravis Ultrasound.
#           Possible values: 240, 220, 260, 280, 2a0, 2c0, 2e0, 300.
#   gusirq: The IRQ number of the Gravis Ultrasound.
#           Possible values: 5, 3, 7, 9, 10, 11, 12.
#   gusdma: The DMA channel of the Gravis Ultrasound.
#           Possible values: 3, 0, 1, 5, 6, 7.
# ultradir: Path to Ultrasound directory. In this directory
#           there should be a MIDI directory that contains
#           the patch files for GUS playback. Patch sets used
#           with Timidity should work fine.

gus=true
gusbase=240
gusirq=5
gusdma=3
ultradir=C:\ULTRASND
Make sure your Dosbox.conf folder matches this.

Get the AIL30 Driver: http://www.scene.org/file.php?file=%2Fmirrors%2Fscenesp.org%2Fcompilations%2Fblastersound_bbs%2FGUS%2FGAIL3214.ZIP&fileinfo
unzip it and look for: ULTRA.DIG and ULTRA.MDI (Rename ULTRA.dig to SB16.DIG and ULTRA.MDI to MPU401.MDI
go into RES then click sound.
Put those files into sound (make sure you back up the old ones.)

Open up dosbox.conf again.
[autoexec]
# Lines in this section will be run at startup.
mount C:/
mount S ..
S:
cdshock.exe
exit

Make sure your autoexec matches this one or music won't work. Also, make sure you copy RES into C: as well, or there will be no sound.

Hope you benefit from this.

SS1 didn't have support for Gravis Ultrasound. LGS was planning on releasing a patch that added support, but it never saw the light of day.

Off Topic: I got over it by turning that mod off and facing them, suddenly they aren't so scary. I still run from the bigger ones though, lol.

Hmm. Seems there's something wrong with the science deck. Once a sound plays (any sound) the music stops. Only way to fix that is to exit the game and start it back up again. I'll look for a fix and update this thread when done.

I personally like the GUS. Its midi quality is pretty good compared to VDMS. (Samples used are based off of real instruments.) Other than that it has no practical use.

It appears the original link to that driver is all dead, and of-course megaupload is gone forever. does anyone still have this driver?

Added a working link in the first post.

I would appreciate if someone could create an archive with the actual necessary files and link it here. Then I will attach it at the top. I'd do it myself but I cannot find an ULTRASND411 file in Gravis ULTRASND Files.rar (folder of that name though) and I don't have the time atm to figure out what Scorpion was referring to.

Oh well. I'll just attach all the files we have now to the first post and repeat my request that once someone has figured out what is actually needed they throw those files in one archive which we can host here.

Bit of necro never hurts, if it's for a worthy reason, which this is.

I'm a Linux user, so I actually prefer Timidity or Fluidsynth (I think it doesn't actually matter that much which softsynth is used, except for some effects; at least I can not hear any difference between FluidSynth and Timidity++ if I use the same soundfont and similar effect settings - their defaults differ somewhat).

I think the GUS support is just a nice thing to have and test out - some games still sound better with GUS support than any soundfont I've used (with GM emulation). So, although the GM is quite good in this case, GUS would be nice to compare to - and the GUS support is almost there! At least it was complete and working with the floppy version. Too bad the floppy version is low-res only (and with mono digital samples / non-directional sound or something, though I'm not sure about the differences).

[OT]: With games, I find that often times a bigger soundfont with gigabytes of samples is worse than a smaller one. I think this has something to do with the instruments not being balanced the way the game composers had when they made the music; these old games have no knowledge of what is being used for the synthesis. IMO, MT32 (emulation - don't own the real thing) is usually best option if the game supports it, and GM is usually inferior to GUS support if both are available. Often GM is even worse - despite the soundfont being used - than AWE32, although that only had a 512kb 1MiB ROM! (and, sadly there is no AWE32 emulation available, only GM soundfonts which do not sound anything like the real thing!)

But these things are very subjective, I must admit. And - as it is said - whatever the user heard first (back in the day) will sound best forever for him/her  [/OT]