Musical archaeology

I got my first PC (a 286) in the early 90s, and one of my favorite activities at the time was playing games. In particular, I loved playing the LucasArts and Sierra graphical adventures (like Secret of Monkey Island and the Space Quest series). At the time, PC hardware was expensive, and in particular a sound card was considered a luxury. Most of these games could play rudimentary music through the PC speaker, like this:


It turns out that these games were also able to play much, much better music if you had the right hardware in your PC. Here is the same game on a Roland MT-32:


Remember that this is the same exact game, that came on 3 floppy disks, running on the same 286! There was no CD with hundreds of megabytes of orchestral scores. And yet, the music is all there, amazingly rich, deep, and polyphonic. To understand how this all worked, a little bit of musical archaeology is necessary.

Throughout the 80s and early 90s, the next best thing to the PC speaker was an AdLib sound card:

(c) Wikipedia

This sound card was reasonably affordable, and generated music by a process called FM synthesis: mix certain frequencies, produced by independent generators, to produce music. If you mixed the frequencies in the right way, you could simulate various instruments. The music still sounded pretty synthetic, but it was a big step up from the PC speaker. One advantage of the AdLib card is that the music could encoded very efficiently -- the game would simply store the frequencies, durations, and volume for the notes that make up the music, and that's it. This is how a game like Secret of Monkey Island could have reasonably rich AdLib music and still fit on 3 floppies.

At around the same time, Creative Labs started to develop the Sound Blaster series:

(c) Wikipedia

These cards could also do FM synthesis (so they were "AdLib compatible"), but they also had a digital sound chip that could play WAV files, or recorded sounds. These sound a lot more realistic, after all they were recorded from real instruments! The sounds, however, took a lot more storage, since the compression was poor. Games that used WAV music sounded a lot better than AdLib, but also took a lot more storage.

Lost in all this is the incredibly rich and largely forgotten history of the Roland MIDI hardware, like the MT-32:

(c) Wikipedia

These modules used the MIDI protocol (Musical Instrument Digital Interface) to receive information about what notes to play, along with "hints" (like sustain, echo, and so on). Like in the case of the AdLib, the music was encoded very efficiently, so it could easily fit on a floppy. The reason this music sounded so incredible is that the Roland hardware had inside it hundreds of rich and detailed "samples" of the instruments it was asked to play. When the game instructed the Roland to play middle-C on a piano, the Roland could render this note by modulating its internal sample of a high-quality piano.

The downside of Roland's hardware is that it was expensive. While an AdLib or Sound Blaster card could be had for around $50, Roland's modules cost over $500 -- a small fortune at the time, so few could afford them. Ironically, the musicians at LucasArts and Sierra composed most of the game music on Roland hardware, and included it in the games, but then also shipped "downgraded" versions of it for the AdLib cards.

Creative Labs tried to compete with Roland by means of a technology called "wavetable synthesis". This was similar to the way the MIDI protocol works: the game would tell the card to play certain notes, and the card would have pre-recorded sounds for various instruments. An example of this is the Sound Blaster AWE32 card, which prominently featured the wavetable technology. The problem with this approach is that memory was still expensive, so in order to stay affordable, these cards shipped with limited storage for these sounds, and therefore had fewer instruments sampled at lower quality. Furthermore, the AWE32 protocol was not fully compatible with MIDI, so it was harder and somewhat more awkward to program.

The advent of cheap CDs, at around the same time, eventually rendered the whole issue moot: games could now afford to ship with an entire CD of pre-rendered, high-quality music, so there was no need for expensive MIDI hardware. Roland came out the loser in all of this: it stopped producing PC hardware entirely and today focuses exclusively on other segments of the market.

One nice side-effect of this struggle, that exists to this day is the advent of General MIDI or GM. This was a protocol that standardized the meaning of instruments so that when a program told the MIDI hardware to play instrument #4, everyone agreed that this would mean a saxophone, say. Most modern hardware today (including PCs and Macs) support General MIDI and have sets of instrument samples licensed from Roland for this exact purpose.

Another development related to this, is the advent of sound fonts. These are basically richer sets of instrument samples that can be used instead of the standard ones that come with General MIDI, and therefore can make the same MIDI hardware sound a lot better when playing the same tune.

Let's take a brief interlude and listen to the history of PC audio as told by Monkey Island:


Today you can still enjoy these adventure classics on emulators, such as the excellent ScummVM engine. In terms of sound emulation, here are your options in ScummVM:

• PC speaker
  
• AdLib (FM synthesis)
  
• SoundBlaster (in FM synthesis mode, or to play WAV samples, if any)
  
• MIDI
  

For the MIDI category, there are the following sub-options:

• Use the General MIDI hardware in your PC, with the standard instruments.
  
• Use MIDI with a sound-font, to significantly improve the quality of the music.
  
• Use a Roland (or equivalent) MIDI hardware attached to your PC.
  

For the purist, a Roland MT-32 can be obtained fairly easily on eBay for around $50 (you will need an external MIDI interface in your PC, however). If you enjoyed these games in the past, you owe it to yourself to try them again with a sound-font. I recommend Shan's excellent (and free!) sound font which is reasonably close to what you'd get out of a Roland. Here's how to use a sound-font in ScummVM:

• First, you need a reasonably fast PC (at least 1GhZ; ScummVM uses software emulation for sound-fonts.)
  
• Click on the "Options" button.
  
• Select the "Audio" tab, and set the "Music Driver" to "FluidSynth".
  
• Select the "MIDI" tab, and set the "SoundFont" path to your sound-font file.
  
• Launch the game, and be amazed.
  

In closing, here are two more beautiful pieces from Loom and Space Quest 1, as rendered on the Roland:



References:

• The History of PC Game Midi
• ScummVM Forums: Question about MT-32
• ScummVM Forums: How to tune your ScummVM sound