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 games use the GUS

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

Native GUS

Approximately 40 games have native GUS support. These titles use the card’s hardware mixing to play tracker-style music, uploading their own samples directly 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.

Notable native GUS games

• Star Control II
• Doom
• Epic Pinball
• One Must Fall: 2097
• Jazz Jackrabbit
• Tyrian

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

Native GUS games typically need only gus = on in the config. Select “Gravis UltraSound” (or similar) in the game’s setup utility. No patch files or TSRs are required.

[gus]
gus = on

Gravis UltraMID

Around 100 games support the GUS through UltraMID, a MIDI translation layer. These games send standard MIDI commands (just like they would to a Roland MT-32 or General MIDI device), and the UltraMID driver translates them into GUS hardware calls, loading the appropriate instrument samples from disk.

The result can sound very good — somewhere between FM synthesis and true General MIDI — but it requires the GUS patch files to be installed. The patches must be placed in the directory pointed to by ultradir (default C:\ULTRASND), with the MIDI instrument bank in a MIDI subdirectory.

Some UltraMID titles also require ULTRAMID.EXE to be loaded as a TSR before starting the game. When this is the case, add it to the [autoexec] section:

[gus]
gus = on

[autoexec]
C:\ULTRASND\ULTRAMID.EXE

Tip

If the game’s setup utility offers both “Gravis UltraSound” and “GUS MIDI” (or similar), try the native GUS option first — it usually sounds better. Fall back to the MIDI/UltraMID option if the native one produces no music.

Notable UltraMID games

• Hocus Pocus
• Rise of the Triad
• Raptor: Call of the Shadows
• Blake Stone: Aliens of Gold
• Turrican II

For a comprehensive list of games with GUS support (both native and UltraMID), 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 (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 UltraMID games.

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 IO 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.