Gravis UltraSound

The Gravis UltraSound (or just GUS) was released in 1992 by an unlikely manufacturer: Canadian joystick company Advanced Gravis. Its audio capabilities were far ahead of anything else on the consumer market — wavetable synthesis, stereo sound, and up to 32 channels of simultaneous playback.

The catch? The GUS made no attempt at backwards compatibility with AdLib or Sound Blaster cards. Programs had to be written specifically for it. Many DOS gamers kept a Sound Blaster alongside their GUS for titles that lacked native support — and in DOSBox Staging, you can do the same by enabling both devices in your configuration.

Another quirk: unlike most sound cards, the GUS shipped with no built-in instrument sounds. All voices had to be loaded from disk via “patch files” at driver load time. Due to licensing restrictions, these patch files can’t be distributed with DOSBox Staging, so you’ll need to obtain them separately.

Where the GUS truly shone was in the demoscene and tracker music community. Second Reality by Future Crew, widely considered one of the greatest DOS demos ever made, was designed to sound its best on a GUS. Games with native GUS support, like Star Control II, also benefited enormously from its superior audio capabilities.

How programs use the GUS

Software used the GUS in several distinct ways. Understanding the difference is important because each requires a different DOSBox configuration.

Native support

These games use the card’s hardware mixing directly, uploading their own samples to the GUS’s on-board RAM — no patch files or drivers needed. This is the GUS at its best: crystal-clear multi-channel audio mixed in hardware with a very low noise floor. Native GUS games need only gus = on in the config. Select “Gravis UltraSound” (or similar) in the game’s setup utility.

[gus]
gus = on

Notable native GUS games

• Al-Qadim: The Genie’s Curse (1994)
• Command & Conquer (1995)
• Discworld (1995)
• Epic Pinball (1993)
• Jazz Jackrabbit (1994)
• One Must Fall: 2097 (1994)
• Simon the Sorcerer (1993)
• Star Control II (1992)
• Tyrian (1995)
• Zone 66 (1993)

All demoscene productions with GUS support also fall into this category — they upload their own instrument samples and use the hardware mixer directly.

GUS MIDI with patch files

These games have a built-in GUS driver that sends MIDI commands and loads instrument samples (patch files) from the ultradir directory to use as wavetable instruments. The GUS acts as a MIDI synthesiser — the result can sound very good, somewhere between FM synthesis and true General MIDI. The patch files must be placed in a MIDI subdirectory under ultradir (default C:\ULTRASND).

[gus]
gus = on
ultradir = C:\ULTRASND

Notable GUS MIDI games

• Dark Sun: Shattered Lands (1993)
• Doom (1993)
• Dune II (1992)
• Gabriel Knight: Sins of the Fathers (1993)
• Heretic (1994)
• Hexen (1995)
• Lands of Lore: The Throne of Chaos (1993)
• Rise of the Triad (1995)
• Warcraft: Orcs & Humans (1994)
• Warcraft II: Tides of Darkness (1995)

UltraMID

These games have no GUS-specific code at all — they send standard MIDI commands as if talking to a Roland MT-32 or General MIDI device. The ULTRAMID.EXE TSR provided by Gravis intercepts these MIDI commands and translates them into GUS hardware calls, loading instrument samples from the patch files on disk. Load ULTRAMID.EXE before starting the game:

[gus]
gus = on
ultradir = C:\ULTRASND

[autoexec]
C:\ULTRASND\ULTRAMID.EXE

Notable UltraMID games

• Betrayal at Krondor (1993)
• Eye of the Beholder (1991)
• Hocus Pocus (1994)
• Indiana Jones and the Fate of Atlantis (1992)
• Master of Orion (1993)
• Monkey Island 2: LeChuck’s Revenge (1991)
• Sam & Max Hit the Road (1993)
• The 7^th Guest (1993)
• Ultima Underworld: The Stygian Abyss (1992)
• X-COM: UFO Defense (1994)

Tip

If a game’s setup utility offers both “Gravis UltraSound” and “General MIDI” (or similar), the GUS option usually sounds better — it means the game has a built-in GUS driver. Fall back to the General MIDI option with UltraMID if the GUS option doesn’t work.

For a comprehensive list of games with GUS support, consult the official GLIST.TXT compatibility list maintained by Gravis:

• gravisultrasound.com
• retronn.de mirror
• dk.toastednet.org mirror

Setting up the GUS environment

For games that need the patch files (GUS MIDI and UltraMID titles), you’ll need to set up the GUS directory structure. The expected layout is:

C:\ULTRASND\
├── MIDI\
│   ├── ACBASS.PAT
│   ├── ACPIANO.PAT
│   ├── ... (instrument patch files)
│   └── DEFAULT.CFG
└── ULTRAMID.EXE

The patch files cannot be distributed with DOSBox Staging due to licensing restrictions. Search online for “GUS patch files” or “GUS MIDI patches” to find them. Several freely available patch sets exist.

Once the files are in place, ensure ultradir points to the correct location in your DOSBox config:

[gus]
gus = on
ultradir = C:\ULTRASND

Note

Native GUS games and all demos do not need the patch files — they upload their own instrument samples. You only need the ULTRASND directory setup for GUS MIDI and UltraMID games.

Hardware configuration

The gusbase, gusirq, and gusdma settings configure the I/O base address, interrupt, and DMA channel of the emulated GUS. The defaults (base address 240, IRQ 5, DMA 3) are chosen to avoid conflicts with the Sound Blaster card, allowing both to coexist. Some games and demos expect the GUS factory defaults of base address 220, IRQ 11, DMA 1. Note that certain versions of the DOS/4GW extender cannot handle IRQs above 7, so IRQ 11 may cause problems with those titles.

GUS-only configuration

If you want to emulate a system with only a GUS and no Sound Blaster (as some purists had in the 1990s), disable the other sound devices:

[sblaster]
sbtype = none
oplmode = none

[gus]
gus = on

This can be useful for games where the GUS and Sound Blaster interfere with each other, or when you want to ensure a game uses its GUS code path exclusively.

Mixer channel

The Gravis UltraSound outputs to the GUS mixer channel.

Configuration settings

Gravis UltraSound settings are to be configured in the [gus] section.

Note

The default settings of base address 240, IRQ 5, and DMA 3 have been chosen so the GUS can coexist with a Sound Blaster card. This works fine for the majority of programs, but some games and demos expect the GUS factory defaults of base address 220, IRQ 11, and DMA 1. The default IRQ 11 is also problematic with specific versions of the DOS4GW extender that cannot handle IRQs above 7.

gus

Enable Gravis UltraSound emulation. Many games and all demos upload their own sounds, but some rely on the instrument patch files included with the GUS for MIDI playback (see ultradir for details). Some games also require ULTRAMID.EXE to be loaded prior to starting the game.

Possible values: on, off default

gusbase

The I/O base address of the Gravis UltraSound.

Possible values: 210, 220, 230, 240 default, 250, 260.

gusirq

The IRQ number of the Gravis UltraSound.

Possible values: 2, 3, 5 default, 7, 11, 12, 15.

gusdma

The DMA channel of the Gravis UltraSound.

Possible values: 1, 3 default, 5, 6, 7.

ultradir

Path to the UltraSound directory (C:\ULTRASND by default). This should have a MIDI subdirectory containing the patches (instrument files) required by some games for MIDI music playback. Not all games need these patches; many GUS-native games and all demos upload their own custom sounds instead.

gus_filter

Filter for the Gravis UltraSound audio output.

Possible values:

• on default – Filter the output. This applies a 1^st order low-pass filter at 8 kHz (lpf 1 8000).
• off – Don’t filter the output.
• <custom> – Custom filter definition; see Custom filter settings for details.