Gravis UltraSound


The Gravis UltraSound or GUS is a sound card for the IBM PC compatible system platform, made by Canada-based Advanced Gravis Computer Technology Ltd. It was very popular in the demoscene during the 1990s.
The Gravis UltraSound was notable at the time of its 1992 launch for providing the IBM PC platform with sample-based music synthesis technology, that is the ability to use real-world sound recordings rather than artificial computer-generated waveforms as the basis of a musical instrument. Samples of pianos or trumpets, for example, sound more like their real respective instruments. With up to 32 hardware audio channels, the GUS was notable for MIDI playback quality with a large set of instrument patches that could be stored in its own RAM.
The cards were all manufactured on red PCBs, similar to fellow Canadian company ATI. They were only a little more expensive than Creative cards, undercutting many equivalent professional cards aimed at musicians by a huge margin.

Versions

UltraSound (Classic)

The first UltraSound was released in , along with the Gravis PC GamePad. The Ultrasound was one of the first PC soundcards to feature 16-bit, stereo. The final revision of the GUS Classic features of onboard RAM, hardware analog mixer, and support for 16-bit recording through a separate daughterboard based on the Crystal Semiconductor CS4231 audio codec.

Reception

Computer Gaming World in 1993 criticized the UltraSound's Sound Blaster emulation and lack of native support in games, stating that "it is hard to recommend this card to anyone other than a Windows MIDI musician".

UltraSound MAX

Released in 1994, UltraSound Max is a version of the GUS with a CS4231 codec on board, 512 kB of onboard RAM, and Panasonic/Sony/Mitsumi CD-ROM interface slots. CS4231 provides support for Windows Sound System specs, although the IO port range doesn't match the WSS hardware, and can be used for SoundBlaster emulation. The software CD includes a demo that featured "3D holographic sound" through the use of software HRTF filters.
Image:Gravis UltraSound PnP Pro V1.0.jpg|thumb|Gravis UltraSound PnP Pro

UltraSound Plug & Play (PnP)

Released in 1995, the Ultrasound Plug & Play was a new card based on AMD InterWave technology with a completely different sound set. Supposedly Synergy acted as the ODM-producer for it. The card features 1 MB of sound ROM, no onboard RAM, and an ATAPI CD-ROM interface. A 'Pro' version adds 512 kB of on-board RAM required for compatibility with the GUS Classic.
In 2014, a RAM adapter for the 72-pin SIMM was produced by retro-computer enthusiasts that made it possible to install 16 MB of RAM on the 'Pro' version without any modifications to the card.

UltraSound ACE (Audio Card Enhancer)

Released in 1995, this budget version of UltraSound Classic has 512 kB of RAM, and has no game port or recording ability. Marketed as a competitor to Wave Blaster-compatible cards, it is supposed to be installed alongside a SoundBlaster Pro/16 card as a sample-based synthesis upgrade. A prototype of this card was named "Sound Buddy".

UltraSound CD3

An OEM version of UltraSound Classic produced by Synergy, with of RAM. It features AT-BUS CD-ROM interfaces following Sony, Mitsumi and MKE/Panasonic standards. This is the only Gravis sound card with a green circuit board It is similar to a few card clones, including the Primax SoundStorm Wave and the AltraSound.

UltraSound Extreme

Released in 1996, the UltraSound Extreme is a 3rd party OEM system combining the UltraSound Classic with an ESS AudioDrive ES1688 sound chip for Sound Blaster Pro and AdLib emulation. It was produced by Synergy as was the ViperMAX. It has 1 MB RAM by default and cannot be upgraded any further.

UltraSound Clones and OEM cards

All clones use the original Gravis GF1 or the AMD InterWave soundchip.
  • Primax SoundStorm Wave – there are two variants of cards from the well known scanner and mouse producer. Re-labeled Altrasound as Sound M-16B and different Sound M-16C with 4x CD-ROM Interfaces.
  • D&B UltraWave – this card has 512 kB onboard RAM by default, upgradeable to 1024 kB RAM using a 512 kB SOJ-40 DRAM chip. Has a DIP socket for a 16 kB boot ROM and an IDE interface.
  • Synergy ViperMAX – same card later repacked as UltraSound Extreme, but with only 512 kB RAM on board.
  • Expertcolor MED3201 – probably the only card with cut-down variant of GFA1 chip - AM78C200 InterWave LC. First series was with standard Am78C201KC.
  • Compaq Ultra-Sound 32 – one of the last InterWave cards was designed for Compaq Presario desktops. Newer "C" revision of InterWave - AM78C201AKC and TEA6330T fader. Produced by STB Systems.
  • STB Systems Soundrage 32 – standard InterWave card missing SIMM slots and IDE interface. There was "Pro" variant with 512 kB RAM. AM78C201KC chip.
  • Core Dynamics DYNASonix 3D/PRO – features additional DSP chip that offered a graphic equalizer and additional sound FX presets.
  • Philips PCA761AW – card design closely resembles the "AMD InterWave OEM Design" prototype. Has a footprint for 512kb RAM, often left unpopulated. AM78C201KC chip.
  • Reveal WAVExtreme 32 – AM78C201KC based design. Comes without RAM and has no sockets/footprints to add any.
  • As of February 2015 there have been efforts by hobbyists to produce named ARGUS.
  • PicoGUS – Pico Pi based design started in 2022 by Ian Scott. Community support built up over the subsequent years. As of 2024 its emulation has similar compatibility to an original GUS. The PicoGUS also includes support for Tandy 3 Voice like the Tandy 1000, Game Blaster / Sound Blaster 2.0, and intelligent mode MPU-401 support.
  • MK1869 Xtreme – A sound card with both AMD InterWave and ESS ES1869 sound chip made by Marmes and Keropi of in 2025. The card features 1MB of sample ROM and 8MB of RAM soldered on board. At release time initially 4MB cards were also available, and provided soldering pads on the back side to add another 4MB of RAM. The card also features a wavetable daughterboard header, AC97 front panel audio header and connectors for PC Speaker and CD audio.

    GF1

The GF1 was co-developed by Advanced Gravis and Forte Technologies and produced by Integrated Circuit Systems under the ICS11614 moniker. The chip was derived from the Ensoniq OTTO chip, a next-generation version of the music-synthesizer chip found in the Ensoniq VFX and its successors.
The GF1 is purely a sample-based synthesis chip with the polyphony of 32 oscillators, so it can mix up to 32 mono PCM samples or 16 stereo samples entirely in hardware. The chip has no built-in codec, so the sounds must be downloaded to onboard RAM prior to playback. Sound compression algorithms such as IMA ADPCM are not supported, so compressed samples must be decompressed prior to loading.
The sound quality of the GF1 is not constant and depends on the selected level of polyphony. A CD-quality 44.1 kHz sample rate is maintainable with up to 14-voice polyphony; the sample rate progressively deteriorates until 19.2 kHz at the maximum of 32-voice polyphony. The polyphony level is software-programmable, so the programmer can choose the appropriate value to best match the application. Advanced sound effects such as reverberation and chorus are not supported in hardware. However, software simulation is possible; a basic "echo" effect can be simulated with additional tracks, and some trackers can program effects using additional hardware voices as accumulators.

Sample RAM

The UltraSound offers MIDI playback by loading instrument patches into adapter RAM located on the card, not unlike how instruments are stored in ROM on other sample-based cards. The card comes with a 5.6 MB set of instrument patch files; most patches are sampled at 16-bit resolution and looped to save space. The patch files can be continuously tweaked and updated in each software release.
The card's various support programs use.INI files to describe what patches should be loaded for each program change event. This architecture allowed Gravis to incorporate a General MIDI-compatible mapping scheme. Windows 95 and 98 drivers use UltraSound.INI to load the patch files on demand. In DOS, the loading of the patches can be handled by UltraMID, a middleware TSR system provided by Gravis that removes the need to handle the hardware directly. Programmers are free to include the static version of the UltraMID library in their applications, eliminating the need for the TSR. The application programmer can choose to preload all patches from disk, resizing as necessary to fit into the UltraSound's on-board RAM, or have the middleware track the patch change events and dynamically load them on demand. This latter strategy, while providing better sound quality, introduces a noticeable delay when loading patches, so most applications just preload a predefined set.
Each application can have its own UltraMID.INI containing a set of patch substitutions for every possible amount of sample RAM, so that similar instruments are used when there is not enough RAM to hold all of the patches needed. Unused instruments are never loaded. This concept is similar to the handling of sample banks in digital samplers. Some games — including Doom, Doom II and Duke Nukem 3D — come with their own optimized UltraMID.INI.
The UltraSound cards gained great popularity in the PC tracker music community. The tracker format was originally developed on the Commodore Amiga personal computer in 1987, but due to the PC becoming more capable of producing high-quality graphics and sound, the demoscene spilled out onto the platform in droves and took the tracker format with it. Typical tracker formats of the era included MOD, S3M, and later XM. The format stores the notes and instruments digitally in the file instead of relying on a sound card to reproduce the instruments. A tracker module, when saved to disk, typically incorporates all the sequencing data and samples, and typically the composer would incorporate their assumed name into the list of samples. This primitive precursor to the modern sampler opened the way for Gravis to enter the market, because the requirements matched the capabilities of the GF1 chip ideally. The problem with other sound cards playing these formats was that they had to downmix voices into one or both of its output channels in software, further deteriorating the quality of 8-bit samples in the process. An UltraSound card was able to download the samples to its RAM and mix them using fast and high-quality hardware implementation, offloading the CPU from the task. Gravis realized early on that the demo scene support could be a sales booster, and they gave away 6000 cards for free to the most famous scene groups and people in the scene.