Advanced Gravis

In 1991, Advanced Gravis and Forte Technologies launched their joint venture Sound Blaster Pro competitor - the Ultrasound (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 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 provided compatibility with Sound Blaster.

Gravis UltraSound

FM synthesizer: None.
Main chip: Gravis GF1.
CD quality playback, wavetable onboard (256K RAM), but lacks hardware Sound Blaster (or even Ad Lib) compatibility.
Audio codec: Crystal CS4231A-KL.
Price when New: $110

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. 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.

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.

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.

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
Price when New: $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 CS-4231 helps but not enough.  Also, its dependence on NMI 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: ?
Audio codec: ?
48 kHz playback, ?
Price when New: $100

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.

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