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Advanced Gravis Ultrasound

Multimedia PC Sound Card

A PC sound card with 16-bit digital audio and an Ensoniq-derived synth section for just over £200? Is it, wonders Brian Heywood, too good to be true?

Every now and then a product surfaces that causes a frisson of excitement, people start saying, 'have you heard about...' and rumours about the features of the device in question become a topic of conversation. Sometimes such products even live up to their whispered reputation! The Advanced Gravis Ultrasound is one such product, and the rumours are not surprising when you consider at its price/performance ratio: 16-bit sound and a wavetable synthesizer on a PC card for just over £200.

So what exactly is it? The Ultrasound is a multimedia sound card. This means that it can provide all the audio facilities that a Windows program (or game) might need. To do this it needs to be able to do a number of things; I've already mentioned the synthesizer and the digital audio replay, but the card also has a MIDI port for driving external sound modules, and a low specification audio mixer for combining the various sound sources. The digital audio replay is not sophisticated enough to behave like a sampling keyboard — it just plays back digital audio data (ie. samples) at a single pitch, suitable for sound effects and 'voice overs'.

The card is really a development from the computer games world, following in the footsteps of the Ad Lib and Sound Blaster — the Ultrasound has been designed to provide high quality 'bangs and crashes' which are compatible with these earlier cards. More interesting from the musician's point of view is that the card is MPC-compatible, so you can use it with Windows 3.1 sequencers such as Cubase Windows and digital audio editors such as Wave for Windows.


The Ultrasound's role as a multimedia sound card means that it has a number of different ways of making a noise, plus the means of controlling the resulting sounds. The sound production elements are: a GM (General MIDI) compatible synthesizer, 16-part multi-timbral and 32-note polyphonic; a digital audio recording/playback section; and a MIDI interface. For sound control there is an audio mixer which allows your computer to mix the internal sound sources with an external audio source (usually a CD player) to produce a single stereo output.

The synthesizer section uses the same technology that Ensoniq use in their 12-bit wavetable sound modules, and the board comes with 512 Kbyte of RAM installed. You might be wondering why a sound card needs to have extra RAM. Well, this is where the wavetables that produce the sounds are stored, the tables being set up by the driver software supplied with the card. The RAM can be upgraded to 1MB (in 256K steps) to allow more complex sounds to be stored on the card.

The digital audio playback section is capable of CD-quality playback but the card (as supplied) can only record at 8-bit resolution. This is presumably to keep the cost down, since an 8-bit digitiser is a relatively cheap option, this being the standard for digital telephony. I can see the logic behind this, since most people will only want to record speech, for which 8-bit sampling is perfectly adequate. Gravis will be releasing a 16-bit input module, but as yet there is no sign of a firm release date for this — I personally would not therefore consider buying this card if I needed the ability to record at the higher resolution in the near future.


The Ultrasound card is a three-quarter length 16-bit ISA card, so you'll need at least a 286 PC/AT to be able to use it. The actual circuit board has quite a large proportion of analogue circuitry on it and is a friendly brownish/red colour — well, it makes a change from the usual green! There are two header blocks that are obviously for the (as yet unavailable) add-on modules, plus some empty sockets for the additional wavetable RAM. I tested the card with both 512K and 768K of RAM installed, but you really need the full 1 MB if you're doing any kind of serious work.

The signal connectors are all on the back panel: stereo line and microphone inputs, stereo line and speaker outputs, and a 15 way 'D type' connector that carries the joystick and MIDI signals. All the audio connectors are stereo mini-jack sockets. Unlike the Sound Blaster and Multisound cards, there is no way to connect the audio output of an internal CD-ROM drive directly to the Ultrasound's PCB. Like the Sound Blaster, the card has a 4 Watt stereo amplifier, which is beefy enough to drive a small set of speakers. Unlike the Sound Blaster there is no external volume control so you must use software control to alter the level.

The review copy of the card came with a MIDI interface cable put together by the distributor, so I was unable to gauge the quality of the one that will be supplied with the card. However, the MIDI functions appear to work fine. I was able to record and play back MIDI using Cubase Windows and the media player; I was not able to test the joystick port, since I do not own such an animal.


The Ultrasound comes with five disks of compressed software, containing the games drivers, Windows drivers, DOS and Windows utilities, patch files, and a DOS-based waveform editor called the UltraSound Studio 8. The games drivers allow you to use the Ultrasound with DOS-based games software designed to use either the Sound Blaster or Ad Lib sound cards. The drivers 'fool' the game into thinking that the Gravis card is a compatible sound generator by catching the sound card commands on the fly and converting them into the equivalent Ultrasound commands.

The DOS utilities allow you to replay digital audio and MIDI files from the DOS command line and let you add sound to your batch files. There is also a utility to play back Autodesk Animator files (*.FLI) in synchronisation with a sound file, giving you the ability to produce very powerful presentations or demos.

The Windows drivers allow you to use the Gravis card with Windows 3.1, giving multimedia aware software access to the digital audio, on-board synthesizer and the external MIDI port. There are also two Windows utilities for controlling different aspects of the cards' operation. The patch files are the wavetables that produce the actual sounds and are downloaded to the card on demand by both the DOS and Windows drivers. One of the interesting points about the Ultrasound is that the sounds are totally 'soft', so you should be able to customise the sounds once wavetable editing software becomes available.

The USS8 recording utility is a comprehensive sound recording and editing system. It allows you to record 8-bit digital audio from either the line or microphone inputs. The editing facilities include the ability to cut and paste sections of the recording, add fades and mix the contents of two or more sound files. The user interface is mouse oriented and uses the concept of an open reel tape machine as its interface model. You need to have at least a EGA monitor to be able to use this software.


The installation of a sound card can be a form of private hell if your PC has lots of other expansion cards installed. Surprisingly, the Ultrasound installation was relatively painless, despite the fact that it needs no less than four different ports/addresses to be configured. There are only two jumper blocks that need to be set up on the card. One defines the base address of the card — which only needs to be changed if another card uses this address. The other jumper block simply allows you to disable the game port, which should only be necessary if you have a joystick port that cannot be disabled.

Once you've installed the card and put the lid back onto your computer, you can run the DOS-based installation software. After decompressing and transferring the files to your PC's hard disk, the software is ready to configure the sound card's I/O ports and DMA channel. You need to have speakers or headphones attached, since the software actually 'talks' you through the installation process. This has to be the way of the future — imagine your computer telling you which buttons you need to press, nagging you about doing a backup, telling you about a pain in the diodes down its left hand side... Gravis may have started something here!


The card's line output seems to have about the same background noise as my semi-pro effects (ie. SPX90, MIDIverb etc.) although — as with all sound cards — this can be affected by the quality of the PC's power supply. Another factor that can affect the noise performance of a sound card is the proximity of other expansion cards, such as video cards; you may need to try the Ultrasound in a number of slots to find the best location.

"The Advanced Gravis Ultrasound card looks like extremely good value for money, especially if you want to hear 16-bit digital audio but don't want to pay for 16-bit recording."

The quality of the sample replay section is a bit hard to determine, since there aren't any 16-bit sound files supplied with the card. The Windows driver is no help here either, as it only supports 8-bit sample replay. As the card can only record at an 8-bit resolution, you can't generate original samples by this route. The 8-bit samples sound clean enough, but this is rather beside the point, since the big thing about the Ultrasound is the 16-bit replay.

The synthesizer output is a big improvement over the cheesy FM sounds that you get from the Ad Lib derived boards, but when compared to other GM modules such as the TG100 and the Multisound, they leave a lot to be desired. The only consolation here is that the patches can be updated by Gravis or other third-party sound programmers at a later date, since they are stored on the PC's hard disk and downloaded to the card just before playback. There should be a completely new set of patches available from Gravis by the time you read this, as well as a Windows-based patch editor, so you will be able to customise the wavetables to suit you.


The Sound Blaster card is becoming quite well supported in the world of DOS music software. As the Ultrasound can emulate the Sound Blaster via the SBOS driver you should be able to run most DOS music packages without too many problems. The Ultrasound does a very accurate simulation of the standard Sound Blaster FM sounds, which seems a bit strange, since the potential sound quality of the Gravis is much better. However, you should be able to alter the default patch files to improve the sound.


This is perhaps the most disappointing aspect of the Ultrasound, since the supplied Windows drivers do not support 16-bit digital audio replay. If you attempt to play a 16-bit sound file you get the dreaded 'Unsupported format' message from Windows. In a way, the 16-bit appellation is a bit of a con; certainly the hardware is there, but if there is no software support, then it might as well be an 8-bit card. Maybe a more accurate description would be '16-bit ready'.

The synthesizer section is more satisfactory, although not completely without its problems. The Ultrasound uses its on-board memory to store the wavetables for the synth sounds. Since there is not enough memory to store all 128 patches, there must be a mechanism for loading the wavetable memory dynamically so that the correct patch is always there when you come to select it. It's a bit like having a percussionist who can only use one drum at a time, though in the course of a particular song s/he might put down one drum and pick up another.

Windows has a such a mechanism — called 'patch caching' — but it is the responsibility of the MIDI software to use it, and quite a few (including Cubase Windows) don't. I hasten to add that this problem is not the fault of the Ultrasound, but rather a result of Windows programmers cutting corners. Programs that do support patch caching include Power Chords and WinJammer, and I imagine that others will follow suit with future releases. Gravis supply a Patch Manager utility that allows you to preload the Ultrasound's wavetable memory to get around this problem; you can even scan through a MIDI file and load any patches that are used (as long as you have enough card memory). This may be a way of getting round the problem, but it's not particularly conducive to creative composing since you must know which sounds you are going to use before you start up your sequencer.

The final niggle with the Windows support software is the very limited mixer application. Although this allows you to control the output of the MIDI synth and wave audio, there is no level adjustment for either the line and microphone inputs or the stereo balance. Whilst this is not a major failing, it just adds to the feeling of incompleteness of the Ultrasound's Windows support.


The Advanced Gravis Ultrasound card looks like extremely good value for money, especially if you want to hear 16-bit digital audio but don't want to pay for 16-bit recording. The improvement in the quality of the synthesizer sounds over cards in the same price bracket is also a compelling reason to choose this board, although I would suggest that you get the extra RAM if you buy it for this. However, the card is badly let down by the supporting software, especially the Windows drivers and the patch files. The problems are all caused by what has been missed out rather than by any fundamental problem with the card itself, which means that the system will improve with time.

The support from the UK distributor (Optech) has been very good, but they have been hamstrung by the Canadian supplier constantly being late with delivering the supporting software and the add-on hardware. Optech's policy has been to update current users free of charge whenever updates do occur. So at least you can be fairly confident that you'll get the software eventually.

So, the whole thing boils down to two choices, depending on what you want to use a sound card for. If you are after a relatively low cost sound card for adding multimedia facilities to your Windows PC, then you could do a lot worse than the Gravis Ultrasound — it also has the advantage that it should improve with age (as more software becomes available). It will also allow you to play any Sound Blaster compatible games if you're into that kind of thing.

If, on the other hand, you are looking for a system to produce high quality music and sound or to act as part of a high performance multimedia authoring system, then the Ultrasound is not quite there yet. Give it six months or so and the situation may well be different — in the meantime there is always the Turtle Beach Multisound or the new Sound Blaster Pro 16/Wave Blaster cards to cover the high end, if your budget stretches that far.

Further information

Gravis Ultrasound £209.98 inc VAT.

Optech, (Contact Details).


There is nothing new about the idea of adding sound capabilities to your PC by the addition of an expansion card. The first significant PC card that could compete with mainstream MIDI modules was the IBM Music Feature card that featured a Yamaha FB01 synthesizer. The Music Feature was not a great success due to its non-standard MIDI implementation, and was never released in this country. Roland's LAPC1 card avoided this ignominious fate by virtue of its MPU401 compatibility, allowing almost all currently available PC software to use it. The other main impetus to the development of sound on the PC was the computer games market, which spawned first the Ad Lib card and then the Sound Blaster, which added the ability to replay 8-bit digital audio (ie. samples).

When Microsoft designed the multimedia element of their new Windows operating environment, they decided to bring the three strands of PC music making — MIDI, synthesis and sample recording/replay — onto a single card. A MPC card must also be able to mix the internal sounds with external audio signal sources such as CD audio or the audio output from a Loser Disc player. One final thing that you often find on MPC sound cards is some kind of CD-ROM interface, usually implemented using the Small Computers Systems Interface (SCSI).

Most of the current cards use 8-bit digital audio and a simple form of FM synthesis which rule them out for serious music production — the music industry has simply moved on from this kind of technology — but there are now a number of cards that offer acceptable performance in the studio environment. These can record and play back 16-bit digital audio at sample rates up to 44.1 kHz (CD quality) and invariably use wavetable technology to produce the synthesised sounds. The first of these was Turtle Beach's Multisound card (reviewed in the July '92 SOS) which uses Emu Proteus chips, and this was followed by the Advanced Gravis Ultrasound, using Ensoniq's 12-bit wavetable technology. Creative Labs have also announced a 16-bit digital audio card with Emu chips.

Also featuring gear in this article

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SOS On-line - Your Letters

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SSU Professional PCM Sample Library

Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - Mar 1993

Gear in this article:

Expansion Board (Computer) > Gravis > Ultrasound

Review by Brian Heywood

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