Gravis Ultrasound

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 demo scene in the 1990s.

The Gravis UltraSound was notable at the time of its 1992 launch by providing the IBM PC platform with sample-based music synthesis technology (marketed as "wavetable"), 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 a little more expensive than Creative cards, undercutting many equivalent professional cards aimed at musicians by a huge margin.

The first UltraSound was released in early October 1992, along with the Gravis PC GamePad. The Ultrasound was one of the first PC soundcards to feature 16-bit, 44.1 kHz, stereo. The initial card doesn't fully conform to the Multimedia PC requirement, due to absence of 16-bit audio recording and onboard analog mixer (used to control volume of analog CD, line-in etc. inputs). The final revision (v3.74) of the GUS Classic features 256 kB of onboard RAM (upgradeable to 1024 kB through DIP sockets), hardware analog mixer, and support for 16-bit recording through a separate daughterboard based on the Crystal Semiconductor CS4231 audio codec.

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