In the latest issue of Custom PC magazine, out now, K.G. Orphanides looks back at Roland’s external MIDI synth that revolutionised early PC gaming music.

A glossy black box with a green LCD invites you to ‘Insert Buckazoid’ on its screen. A stirring 1980s sci-fi theme blasts glossy-textured synth tones through the speakers connected to it, as you’re brought up to speed on the continuing exploits of space janitor Roger Wilco. In 1989, Space Quest III leaned into the highest-quality music available on home computer platforms, an external MIDI audio device that was as prohibitively expensive as it was revolutionary. 

When it was released in 1987, the original Roland MT-32 MIDI synthesiser cost £450 in the UK – equivalent to over £1,200 in today’s money, and it didn’t even come with the MIDI interface card you’d need to connect it to your PC.

Roland primarily marketed its MIDI expander module at amateur electronic musicians: a multi-timbral synth-in-a-box that could be controlled by any MIDI keyboard. It proved popular by being significantly cheaper than most rivals, and by supporting 32-note polyphony across up to eight simultaneous voices. 

But the MT-32 would become best known as the pinnacle of IBM PC-compatible gaming audio from the late 1980s to the mid-1990s, and it helped to popularise the fully orchestrated game soundtracks we take for granted today.

What’s in the box?

In 1987, digital synthesis was still a relatively new technology, developed in the 1970s and popularised in 1983 by Yamaha’s DX7 synthesiser. It would become the archetypal sound of the 1980s, with a very different feel to analogue synthesisers’ use of control voltages to determine pitch, gate and trigger signals.

The MT-32 used Roland’s new Linear Arithmetic (LA) synthesis technique, first seen a few months earlier in Roland’s 61-key D-50 keyboard synthesiser. LA synthesis relies on Partials: fundamental sounds to which it then adds effects in order to produce voices. 

These Partials are either stored as pulse code modulation (PCM) sound samples (as used by audio CDs, WAV files and so on) or fully simulated combinations of oscillators, creating the tone. Filters then determine the brightness of the sound by fixing its cutoff frequency, and an amplifier then determines its loudness. The LA chip’s pitch and amplitude envelopes act on the PCM sounds, determining the note produced and its attack, decay, sustain and release. This technique enabled the synth to produce a realistic (for the time) reproduction of genuine instruments.

Alongside the LA chip, you’ll find a dedicated gate array, a reverb chip, a Burr-Brown PCM54 DAC, a clutch of op-amps, and EEPROMs that hold the MT-32’s firmware and PCM sample banks. You can even send custom patches to the MT-32 – specific configurations of effects for the LA synthesis chip to render on a voice from the PCM bank, so you can effectively make new instruments.

Getting into PC gaming

The first IBM PC-compatible game with an MT-32 soundtrack was Sierra’s King’s Quest IV: The Perils of Rosella. Scored for the MT-32 by film and TV composer William Goldstein, the game also supported other audio hardware on release, notably the Yamaha OPL2-based AdLib.

Sierra would carry the flag for the MT-32, recruiting Supertramp drummer Bob Siebenberg to create the soundtrack for Space Quest III and even selling the MT-32 and required MPU-401 ISA MIDI interface card for $550 US (equivalent to around £950 today), with MIDI composition software and two Sierra games of your choice included. 

The MT-32’s original US retail price was $695 US (around £1,200 today). It wasn’t cheap, particularly compared with the AdLib and CMS Game Blaster cards Sierra also sold, but it was the best way to get what the company’s 1989 catalogue describes as ‘a symphony orchestra playing in your living room’.

Other companies took up the challenge, some more enthusiastically than others. Origin Systems supported the MT-32 with some excellent soundtracks from 1990’s Ultima VI and Bad Blood, through to Pacific Strike in 1994. LucasArts/Lucasfilm Games put most of its MT-32 support into its Star Wars titles, such as X-Wing, although some adventure games, including Sam & Max and the Monkey Island titles, received MT-32 MIDI soundtracks. Legend Entertainment, New World Computing and Microprose were also enthusiastic adopters.

UK game development support for the MT-32 included the Bitmap Brothers’ Gods, Adventuresoft/Horrorsoft’s Elvira and Simon the Sorcerer games, Team 17’s Alien Breed, Gremlin Graphics’ Litil Divil and Plan 9 From Outer Space, as well as Ocean Software’s Elf.

Sierra aggressively promoted and supported the MT-32 until the General MIDI standard was published in 1991, which standardised the voice types and program numbers, ensuring that the right instrument sounds were playing the right parts on all compatible devices, although the quality of the voices still depended on your synth. 

The music for Laura Bow II: The Dagger of Amon Ra (1992) was composed on the MT-32, but released with full support for new General Midi audio devices such as the Roland SCC-1. Other studios supported the MT-32 as late as 1997, with the cover disk demo of Bethesda’s The Elder Scrolls: Daggerfall being among the last.

Versions and relations

The MT-32 spawned a host of versions and successors, and became a de facto MIDI standard for other sound card producers before General MIDI was established.

This first ‘old’ version of the MT-32 is easy to spot, based on its port configuration – it had just a stereo pair of 1/4in TRS outputs. If you connect it to a MIDI interface card on any PC faster than a typical 286, it can produce buffer overflow errors due to an insufficient delay between SysEx messages sent to the device. This could be resolved using the turbo button on 386 and 486 PCs or slowdown utilities on later PCs. This doesn’t affect modern PCs using good-quality USB-to-MIDI connectors though – delaySysEx switches are also implemented in a number of popular emulators.

The second ‘new’ version of the MT-32 introduced a functionally undetectable control CPU switch, along with an additional rear TRS stereo headphone port and reduced noise levels. It also added a ROM playback demo mode and introduced some changes to the gate array and ROM chips. It fixed the buffer overflow error affecting faster computers, but it also rectified some firmware bugs on which some game composers had relied, breaking some soundtracks.

The MT-32’s appeal to computer music composers didn’t go unnoticed by Roland, and the company followed it with the screenless Computer Music (CM) range of MIDI devices, based on the LA chip. This included, in 1990, Roland’s first internal ISA sound card, the LAPC-I, which integrated an MPU-401 interface and MT-32-compatible CM-32L synth.

By 1991, General MIDI was standardised and Roland launched its Sound Canvas range with the SC-55, which used Roland’s own GS (General Standard) extension to provide even more voices. A year later an internal version, the Roland SCC-1, was released. Both provided reasonable  MT-32 backwards compatibility, but lacked support for custom MT-32 instrument patches.

These MIDI devices, and many to follow, would be popular with musicians for years, but MIDI music in games was on the wane. Full CD audio was clumsy at first, but as disk capacity and audio compression improved, it would be digitally recorded audio that led game music into the new millennium.

Custom PC — Issue 220 out NOW!

You can read more features like this one in Custom PC #220, available directly from Raspberry Pi Press — we deliver worldwide.

And if you’d like a handy digital version of the magazine, you can also download issue 220 for free in PDF format.