The Gravis UltraSound, also known as GUS, is a 16-bit ISA sound card released in 1992 by the Canadian company Advanced Gravis Computer Technology.
It is powered by the GF1 chip and one of its most notable features is wavetable synthesis, with 256 kB of sample RAM (upgradeable to 1MB). It could play up to 32 channels of hardware audio at 19 kHz or 14 channels at 44.1 kHz. This made it quite popular with PC-based music composers.
There were a number of variations of the original UltraSound. The Max had 512 kB of sample RAM that could be upgraded to 1MB, plus Panasonic, Sony, and Mitsumi CD-ROM connectors. The PnP had two 30-pin RAM slots that could hold up to 8MB of RAM in total. The Extreme adds an ES1688 chip for Sound Blaster Pro and AdLib emulation.
Sales of the Gravis UltraSound and its variants were not enough to sustain the company and it was acquired by Kensington in 1997 and subsequently destroyed in much the same way that Creative Labs destroyed Ensoniq.