DOS Days

Advanced Gravis

In 1991, Advanced Gravis and Forte Technologies launched their joint venture Sound Blaster Pro competitor - the Advanced Gravis Ultrasound (often abbreviated to "GUS"). It could mix 16 voices in 16-bit, with up to 44 kHz playback (CD quality) or 32 voices at 16 kHz playback. Opinions of users generally thought the audio quality from the GUS was better than the Sound Blaster Pro.

One key thing the GUS had was a built-in wavetable, so the processing of samples was done on-board rather than having the CPU dedicate cycles to do the task, and no wavetable daughterboard was required. Because playback was only achievable in 8-bit, Gravis later offered an add-on board called the "16-bit upgrade module". This add-on module was integrated on the board of the later Gravis Ultrasound Max, released in 1994.

The GUS' downfall was twofold: it didn't have an OPL chip, and it didn't support Sound Blaster 100%. When running in "AdLib mode", the GF1 chip would take over the equivalent of what the OPL chip did on other cards, and software drivers provided compatibility with Sound Blaster.

This page focusses on the audio hardware from Advanced Gravis. If you are looking for gaming controllers, please visit the dedicated Gravis Controllers page.

Gravis UltraSound   

Introduced: 1991
FM synthesizer: None
Main chip: Gravis GF1
Audio codec: Crystal CS4231A-KL
Plug & Play: No
Prices: $110 (1991), $129 (Nov 1993), $129 (Jun 1994)

The Gravis GF1 is a proprietary audio signal processor and wavetable synthesizer chip, capable of 16-bit 44.1 kHz audio playback and can record 8-bit sound from 2.0 up to 44.1 kHz in either mono or stereo. It was a derivation of Ensoniq's OTTO synth chip that was used on the Soundscape and VIVO cards. You can add 16-bit recording capability with an optional daughterboard. Gravis also produced another optional daughterboard that implemented CD-ROM interface capabilities for the UltraSound.

It has CD quality playback, an onboard wavetable (256K RAM), but lacks hardware Ad Lib or Sound Blaster compatibility.

Onboard memory can be upgraded to 1 MB using 128K DRAM chips. This increases its capacity for storing wavetable patches to increase the number of sounds available in memory.

To provide Ad Lib and Sound Blaster compatibility, Gravis provided a program called SBOS (Sound Board Operating System) - a TSR driver that you need to load prior to playing a game with Sound blaster or Adlib Compatibility. This program tells the UltraSound's CPU to emulate the FM-synthesized sounds on its wavetable - the resulting sounds are much better than their FM counterparts with respect to realism and clarity. Another program that does the same thing is MEGAEM, which sounds different to SBOS. Regardless of which you use, compatibility isn't 100%. For instance, Descent won't play at all with either.

"We tried two versions of the Gravis UltraSound (GUS) card. The first one had old software drivers and 256K of RAM (into which one must load MIDI patches). It worked great under Windows, but we found it to be less desirable under DOS. We also tested a new version of the card with a 1 MB RAM upgrade and new software drivers. For games that support the card, we found the wave table synthesis and digital audio to be quite acceptable. However, in Sound Blaster emulation, we had less luck. Getting sound from the few games that will work with the GUS emulating a Sound Blaster requires a lot of tinkering. The card uses FM synthesis emulation to provide FM music in a game - a less than optimal solution.
Due to the need for many TSRs, lack of publisher support (less than the AdLib Gold at press time) and poor Sound Blaster emulation it is hard to recommend this card to anyone other than a Windows MIDI musician. We're not saying that for a given game, the GUS won't work, it's just that for the casual gamer wanting Sound Blaster compatibility, we found it is not worth the configuration headaches. The 32-voice wave table synthesis is based on an older Ensoniq technology and sounds very good, though not as good as some of the other wave table products surveyed."
     Computer Gaming World, October 1993


Rich Heimlich said this of the GUS: "Decent Windows card or if you're into using RAM patches. Great MOD and demo card. Also inexpensive but that's due in part to hardware they left off. That results in the need to use TSR's which in turn results in poor SB, FM, GM game support.  Direct support did grow a little which helped its cause but not enough.". Scores were 6 out of 10 and 5 out of 10 for digital and music quality respectively.

In 2022 the same folks that brought us the PCMIDI and Orpheus I sound card started work on a modern-day GUS sound card. This Orpheus II is similar to Orpheus I but provides Ultrasound wavetable instead. The original Vogons thread can be found here.

Install disks v4.11, Windows 3.x, Windows 95, GUS PnP Windows 95, GUS Bonus disks v1.52, OS/2, User Manuals, GUS FAQ

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Gravis UltraSound Max    

FM synthesizer: Gravis GF1
Audio codec: Crystal CS4231A-KL
48 kHz playback, 512K wavetable
Plug & Play: No
Price when New: $249 (1994), $189 (Jun 1994), later $170

Rich Heimlich said this of the Max: "Basically the same as the original UltraSound except for the added 16-bit record feature, CD-ROM interface and higher price. The use of a Crystal Semiconductor CS4231 helps but not enough.  Also, its dependence on NMI (Non-Maskable Interrupts) hinder it with Pentiums and advanced OS's.". Digital quality scored 6.5 out of 10, with music quality 5 out of 10

GUS Max Utilities Disk, User Manuals, GUS FAQ

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Gravis UltraSound ACE   

FM synthesizer: Gravis GF1
Audio codec: ?
48 kHz playback, ?
Price when New: $119 (retail), $99 (street)

"Gravis is about to release an Audio Card Enhancer, imaginatively called the Ultrasound ACE.
Unlike other wavetable upgrade cards on the market, the Ultrasound ACE doesn't need any special connectors or adaptors and is the only one that works with any eight or 16-bit sound card. It plugs directly into an expansion slot on the PC and co-exists with the sound card already installed.

As well as offering 32 voices of professional wavetable synthesis, the Ultrasound ACE adds the benefits of 16-bit, multichannel digital audio - which in real terms means super-sound ahoy!
The new Ultrasound ACE should be on the shelves this month with a price tag of around £75."

PC Zone Issue 27, June 1995
"An even less expensive way to get wavetable sound is to add the UltraSound ACE (Audio Card Enhancer) to your current sound card. The ACE fits in a PC expansion slot and connects to your existing sound card's line-out jack. While Advanced Gravis expects the ACE to be a boost to your existing sound board, you can use it on its own as an Ultrasound-compatible sound card-that is, if you can do without the ability to record audio, a CD-ROM interface, and a joystick port The ACE produces pleasing wavetable sound, and your existing sound card can supply Sound Blaster effects and music simultaneously.

As a bonus, Advanced Gravis throws in a CD-ROM packed with 14 shareware games - a nice change from the business- and music-oriented software that comes with most cards. "

Electronic Entertainment, 1994-1995


Rich Heimlich said this of the Ace: "The best of the UltraSound family for most people. Still doesn't provide acceptable compatibility with existing standards and doesn't address any of my concerns with the other Ultrasound cards. But if you like its features and the software you're using supports it natively then at least you could get it inexpensively.". The score for digital quality was 6 out of 10, with music quality coming in at 5 out of 10.


Installation Disks v4.00

Gravis UltraSound Plug & Play / Pro   

Introduced: 1995
FM synthesizer: None
Main chip: Gravis GF1 (AMD InterWave AM78C201KC)
Audio codec: None
Plug & Play: Yes
Part #: 906-0087-00
FCC ID: HYN412-0066-AA
Known Board Revisions: 1.0, 3.0

The Gravis UltraSound Plug & Play added Windows 95 Plug & Play (PnP) compliance to the GUS line-up. It still had the built-in 256 KB 32-voice wavetable of the original card, and could playback and record at up to 48 kHz in 16-bit quality like the GUS Max. It also got the IDE CD-ROM interface from the GUS Max.

To get Ad Lib or Sound Blaster support, it's just like the original GUS - software emulation only.

The memory upgrade slots support up to 8 MB using 30-pin SIMMs to increase the card's capacity for storing custom wavetable patches to increase the number of sounds available in memory. Each slot supports different-sized SIMMs, so you can optionally use a combination of 256 KB, 512 KB, 1 MB, or 4 MB SIMMs in these.

A Gravis UltraSound Plug & Play Pro version was also released, which was the same card but with 512 KB memory installed from factory, and was bundled with a microphone. This allowed for dynamic effects processing from the InterWave chip.

Both cards came bundled with Cakewalk Express and SoundForge XP software, as well as CD-ROM with over 100 MB of games and demos.

Windows 95 Installation Disks v1.01

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Gravis UltraSound VIP/ViperMAX/Extreme  


Introduced: 1995
FM synthesizer: Gravis GF1 + ESS AudioDrive 1688
Audio codec: ?
Onboard memory: 512 KB (VIP), 1 MB (ViperMAX and Extreme)
44 kHz playback: Yes, 16-bit
Price when New: $100
FCC ID: IAX-VIPER10 (UltraSound VIP)

DOS Days contributor Eirik Øverby contributed the details on this incredible sound card. The Extreme was possibly the last UltraSound released. It's key feature was that it included an embedded ESS AudioDrive 1688 chip to provide full Ad Lib and Sound Blaster compatibility - something that was lacking on all earlier GUS cards.

The ESS chip provides the board with full Ad Lib, Sound Blaster 2.0 and Sound Blaster Pro compatibility.

The Extreme was actually created by an authorised third-party, called Synergy. They created 3 separate variants: first to come was called Ultrasound VIP. This was followed by ViperMAX, and finally Ultrasound Extreme.

The VIP got a memory socket that supported a further 512 KB SOJ module. The ViperMAXand Extreme models got two 512 KB banks soldered to the board and had no memory upgrade sockets.

One of the best things about these cards is their ability to use both the GF1 and ESS at the same time - either GF1 for music audio and ESS for sound effects, or vice versa. The cards however, are *not* General MIDI compatible, so playback of GM audio with this card might be hit and miss. Given that the patch set is loaded into the onboard RAM from software, you can switch out the patch set that gets loaded, and several exist out in the wild (both 512 KB and higher-quality 1 MB sets).

These images are reproduced here with kind permission from Tomasz Maciejewski.

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Games Titles That Use the GUS Hardware Mixing Capabilities

The following games make use of the Gravis Ultrasound's hardware mixer. This typically resulted in a higher quality audio outputs:

  • Archon Ultra
  • Crusader: No Remorse
  • Crusader: No Regret
  • Death Rally
  • DOOM v1.2 or below
  • Epic Pinball
  • Extreme Pinball
  • Jazz Jackrabbit
  • The Lemmings Chronicles
  • One Must Fall 2097
  • Pinball Arcade CD-ROM (Pinball Dreams & Pinball Dreams II)
  • Pinball Fantasies
  • Pinball Illusions
  • Silverball
  • Star Control II
  • Turrican 2
  • Zone 66