Gravis Ultrasound

Gravis Ultrasound or GUS is a sound card for the IBM PC compatible system platform. It was very popular in the demo scene in the 1990s, due to its superior sound quality compared to similarly-priced soundcards of its time. Gravis understood early on that to get the demo scene's support would be a sales booster, so they gave away 6000 cards for free to the most famous scene groups and persons. The scene then quickly changed from being mostly Sound Blaster supporting to almost exclusively support the GUS. Many demos and intros made in the 90s do not work with anything but.

Contents

1 History 2 Technical Specs 3 Sources 4 External links

History

The concept of music in games was carried out by the meager PC-speaker since the PC's inception in the early 80s. When a game company called Sierra opted to make music for add-on hardware instead of utilizing the built in PC-speaker the concept changed dramatically. The two companies Sierra eventually started to cooperate with was Roland and Adlib. Sierra opted to make in-game music, starting with King's Quest 4, for the Roland MT-32 and Adlib Music Synthesizer. The MT-32 was the latter superior as it boasted a Wavetable-synthesizer which gives much better sound reproduction than the FM chip residing in the Adlib soundcard. Wavetable cards use a set of sound samples stored on the card to produce instrument sounds, whereas FM cards simply create an approximation of the sound by combining various waveforms generated by a set of onboard oscilators. Because of this, wavetable cards are quite expensive (storing a large sample set onboard drives up the cost) but offer much better reproduction of the music.

It is worth noting that a third player quickly introduced itself onto this new market, Creative Labs. This company, due to good business sense and certain business tactics, managed to take over the market from Adlib, destroying that company in the process, which left Roland its only real contender for a long time.

Since wavetable cards were very expensive in the early 90s and the expressive capabilities of the cheaper FM-synthesizer were rather limited, a new generation of sound standards were needed. The most notable of these are the tracker standard and the General MIDI standard. The tracker format had existed on the Commodore Amiga since the late 80s but due to the PC becoming more capable of producing high quality graphics and sound, the demo scene spilled out onto the platform in droves and took the tracker format with it. Typical tracker formats of the era included MOD, S3M and XM. The MIDI standard, like you would find on the MT-32, consists of instructions on what note to play with what instrument. In other words, it is like a text file containing simple instructions on how to produce the sound. The problem with this was that you needed an expensive sound card with wavetable support in order to produce realistic instrument sounds. FM synthesis may be used in combination with MIDI, but sounds an order of magnitude worse than wavetable synthesis. The tracker format on the other hand, deals with sound differently. This format stores the notes and the instruments digitally in the file instead of relying on a sound card to reproduce the instruments. This opened the way for Gravis to enter the market with its Ultrasound.

The problem with the Creative sound cards playing this format was that it had to mix voices into one or both of its output channels. When waveforms are mixed, there is a loss of quality in the output. The more you mix, the more quality loss you will have. The MOD format had 4 channels, which meant the Creative sound card had to downmix 2 channels. The sound loss of this might not have been huge, but when the ScreamTracker 3 tracker was introduced in 1993 standardizing 16-channels, the existing Creative cards just couldn't keep up. Enter Gravis Ultrasound. Gravis solved the channel problem by having dedicated digital audio output channels for each track. Since the card supported 32-channels, the card almost instantly became the tracker's choice and thus the demo scene's card of choice.

The Ultrasound offered more than just channel support. It could play MIDI by loading instrument patches into RAM not unlike how instruments are stored in ROM on wavetable cards. It supported sample rates of up to 44khz, twice that of the Creative cards available at the time. 16-bit sound could be achieved by adding a daughterboard to the original GUS (this was later integrated with the GUS itself and called GUS MAX), achieving CD quality sound at 44khz at 16 bits/sample. The card was very agreeably priced, although a little more expensive than existing domestic Creative cards, it undercut many equivalent professional cards aimed at musicians by a huge margin, and brought CD quality audio reproduction within the grasp of home PC users. The GUS was also very easy to program for, and it's bounteous onboard memory freed up limited system memory for other tasks, and also allowed games and demos to be run outside of DOS protected mode (i.e. without EMM386 loaded). Programming for the GUS was pretty much a case of fire-and-forget. Upload your samples, tell it what to do, and off it went without much further administration from the programmer.

All that said, there were many problems with the card. The main problem that Gravis faced was the lack of interest from the games industry to support their sound card. The demo scene had taken GUS to its heart but the game industry did not. They continued to support the most common cards such as Sound Blaster and Roland respectively. Many game and software developers also had trouble supporting the card. That the card did not have a FM-chip did not help matters either, as Soundblaster compability was difficult to achieve at best. The shareware games industry were more forgiving and started to release games with native Gravis support aswell as the other sound cards. Famous companies which did this in an early stage were publisher Apogee and developer Epic Megagames. The support eventually got quite broad and Gravis decided to renew their sound card portfolio and release the Gravis Ultrasound MAX. After that, the Gravis Ultrasound PnP cards appeared.

Gravis eventually left the soundcard business, and Sound Blaster reassumed dominance of the low- to mid-range soundcard market.

Technical Specs

The GUS was able to mix multiple channels of audio without using the main CPU, which allowed for complex music and sound effects with a minimal performance impact, one of the selling points to the demo scene. It was remarkable for MIDI playing quality with instrument patches stored in its own RAM, having 32 audio channels.

The GUS MAX boasted the following sound-producing specs:

• Wavetable synthesis (instead of FM)
• 32 digital and/or synthesized voices
• 16-bit, 44.1 kHz CD quality playback
• 16-bit, 48 KHz recording
• 3D holographic sound

Sources

• History of MIDI

External links

• Gravis.com
• The History of PC Game MIDI by Eric Wing
• My Gravis Ultrasound Resource Guide
• FreePats – a free collection of GUS-compatible patches by Eric A. Welsh
• TiMidity++ – a software MIDI synthesizer which can use GUS patches