Unusual Applications of Music and Sound in Retro Games: Part 2 - 3rd Gen Era Computers and Arcades

Welcome back! In Part 1, we explored how developers pushed early-mid ‘80s console and computer hardware beyond its limits. Now we're moving into the mid-to-late '80s era of personal computers and arcades, when sound chips became more sophisticated and composers found even more creative ways to squeeze every last bit of quality from their hardware. This period saw the rise of 4-op FM synthesis, more advanced sample playback, and increasingly complex interactive audio systems in games. Get ready!

Hidden Potential on the AdLib Card

The Yamaha YM3812/OPL2 chip, introduced in the arcades in 1986 and later used in the popular AdLib sound card and compatible cards, was the dominant force in PC game audio before the Sound Blaster card took over with its hybrid FM synth and PCM samples setup, then eventually MIDI and CD redbook audio. While it's known for its FM synthesis capabilities, some developers discovered ways to push it even further.

Using a technique similar to Pulse-Width Modulation (PWM) on the PC speaker, developers could produce 6-bit sample playback on the OPL2 chip. This wasn't something Yamaha advertised, but clever programmers figured it out. Bill & Ted's Excellent Adventure (PC, 1990) showcases this technique in its title track, combining drum samples and a sampled lead synth accompanied by a gnarly 2-op FM synth bass sound. I'm not sure how good this could sound if pushed to its absolute limits since it was barely used, but the result here is pretty solid for the time.

Some PC games supported Stereo/Dual OPL2 setups (included with the Sound Blaster Pro CT1330 but apparently not in later SB cards, which are only backwards compatible with the regular OPL2). There's some conflicting info online, but I can confirm these games support it via this compilation video: Ultima Underworld, System Shock (CD-ROM version), Formula One Grand Prix, Railroad Tycoon Deluxe, Civilization, Harrier Jump Jet, Pirates! GOLD, Colonization, and Simcity 2000. The Pro AudioSpectrum card with Dual OPL2 was also supported by Strike Commander and Wing Commander Privateer. Having two OPL2 chips meant true stereo FM synthesis with 18 channels total instead of 9, creating a richer and more immersive soundscape.

A few games experimented with speech synthesis using the OPL2 chip, including Silpheed by Game Arts. The results were... interesting. While not exactly natural-sounding, it demonstrated yet another creative use of FM synthesis beyond what most people thought possible with the chip.

Early Streaming Audio and Vocal Tracks

As computers became more powerful and storage increased, some games started experimenting with streaming audio - playing back recorded music rather than synthesizing it in real-time. Most of these tracks were still quite short due to hardware limitations, and usually played outside of gameplay, meaning it was more of a preview of what would become standard in the CD-ROM era.

The Halley Project (AMI) - The intro track is a very early example of streaming audio/longer samples fused together to make up a short, recorded live song. It even features decent vocals! The loop timing is not quite there, and the song is short and cheesy, but it sounds remarkably good for the time and is a fun novelty considering most Amiga music wasn't done like this, and almost no vocal tracks existed in games yet. Some of the better later examples include Detonator (AMI), F/A-18 Interceptor (AMI)(stereo, required a RAM extension to boost system memory from 512K to 1MB), Carrier Command (AMI) and ​Starglider 2 (AMI)(vocals)

Captain Blood (STe?, 1988) - Features sample-based streaming audio on the ST, quite an achievement for the system's more limited audio capabilities compared to the Amiga.

Turrican II (STe) - Uses either streamed audio files or a software MOD player for some tracks. The STe, Mega STe, and Falcon 030 models of the Atari ST included the LMC1992 chip, which enabled better audio capabilities.

Sea Strike (A2GS) - Features streaming audio for the title track on the Apple IIGS, showcasing the system's enhanced audio capabilities over earlier Apple II models.

Klax (Lynx) and Qix (Lynx) feature decent quality sample-based music on the Lynx handheld, an impressive feat for a portable system of that era.

Early Vocal Tracks:

Besides the examples from the 1971-1984 article (Double Dribble's infamous national anthem), several other 1980s games experimented with vocal tracks:

• Psycho Soldier (ARC, 1987) - Using a YM3526/OPL1+Y8950 sound chip combo, this game features a full vocal track played back on the Y8950 chip's PCM channel. That chip is essentially an OPL1 with added single-channel ADPCM recording and playback capability, so it's more of a rare case of pushing it to its limits than using the chip in an unintended way. Still, hearing a full vocal pop song in an arcade game in 1987 was pretty mind-blowing!
• Starglider (ST, 1986) - Sample-based vocal track on the Atari ST. I believe this game is using the system's RAM memory here to play a (pretty short) recording of a track with sung vocals
• Twin Eagle (ARC, 1988) - One of the first fully sample-based game OSTs (besides Amiga games), also featuring solid live guitar and vocal recordings in the otherwise sequenced (?) music. Played back on the Seta X1-010 chip in mono (it is capable of stereo). Some parts in this upload don't transition properly making it sound like a skipping record, which I think is an emulation error.
• Mortville Manor (AMI, 1988) - Another early vocal track in an Amiga game, a short jazzy tune where the singer hums the melody and sings the title of the game itself. Yep. Sadly the rest of the game seems to be silent besides a few jingles and some rudimentary speech synthesis.
• Meta Fox (ARC, 1989) - Female rock vocals and live guitar.

Dynamic/Adaptive Music Systems and Interactive Music: Part 2

Extase (AMI, 1990) takes interactive music to a whole new level. Notes or musical patterns are added for each player interaction, and the patterns evolve as the player completes the picture. For 1990, the idea of introducing dynamic music as the game progressed, which the player controlled more directly and which the changing of was a significant part of the experience in itself was near unique - only seen in Jammin' and Moondust (C64, 1983), and Otocky (FDS, 1987) before (possibly Phantasy Star III from April, Wing Commander from September and/or Super Mario World (November, less developed system) as well, since we don’t have a release date for this one).

On a technical level, the soundtrack is also notable for the chopping up and reversing of samples, and the layering of vocal harmonies on single channels. Stylistically, it fully embraces the New Age aesthetics of its time - tribal beats, hypnotic chants, culturally ambiguous soundscapes, meditation vibes, and general weirdness. While games like Shadow of the Beast had sort of fumbled in a similar direction, Extase was more fully realized in its execution.

Wing Commander (1990) features an early soundtrack that reacts dynamically to player actions, though not with seamless (on beat and/or using fades) transitions. While more of a 16-bit era game, the OPL2 sound chip is 1985 tech. More intense music plays when entering combat, a victory fanfare plays when taking out an enemy, a different fanfare plays when ejecting from your spaceship, and so on - 9 battle situations in total, plus variations on mission themes and end of mission themes depending on your performance. While not as smooth as later (and one earlier in Lazy Jones) systems, it was an important step forward in making music respond to gameplay.

The real breakthrough came with Monkey Island 2: LeChuck's Revenge (1991), which introduced the iMUSE system (Interactive Music Streaming Engine). iMUSE changed music on the fly based on your actions, and the transitions were seamless - a major evolution over most previous dynamic music systems. Additionally, the "outside" theme in Woodtick has 7 starting points chosen randomly each time it plays, and there are transitions based on player actions within rooms or sub-areas, giving it an interactive element that makes the world feel more alive.

Space Quest IV (1991) from the same year as MI2 features dynamic transition effects determined by the player's position while moving between various mall stores in the Galaxy Galleria area - another example of developers experimenting with making music more responsive to player actions.

Paula’s Playground: Modulation, Extra Channels, and More

The Amiga's Paula sound chip was something unheard of for a home system in 1985 - designed from the ground up for sample playback, it included four 8-bit PCM channels that could play any sound imaginable in hard-panned stereo. While sample playback might seem straightforward compared to the synthesis-based chips we've been discussing, developers still found creative ways to push this revolutionary hardware beyond its intended limits.

One such way was additional sound channels in software. Paula had four hardware channels by default, which was often noticeable in-game, but creative programmers found ways to add more:

• Turrican II - The title and intro tracks use 7 channels, and so does Hoi's intro track
• OctaMED tracker songs could use up to 8 channels, though from what I've read it was a struggle to increase channels to just 6 or 7 for an actual game while maintaining the same sound quality. Let me know if you can confirm any game that used such tracks!

Another way was community developed software synthesizers that could emulate other sound chips or generate sounds procedurally:

AHX Tracker lets you make music via software synthesis designed to more accurately emulate the sound of the C64 without using any samples. It was made when the Amiga gaming market had already dried up, so it was mostly used for demos. Still, it demonstrates how the flexible Paula chip could be used for synthesis as well as sample playback. SIDmon Tracker essentially does the same thing as AHX, but also allows for samples to be used. While rarely used for games, one good example is Venom Wing. This hybrid approach gave composers the best of both worlds. The aforementioned OctaMED apparently also features a software synth, though I'm unaware of games that use it.

Moving on, there’s also hardware-based modulation on the Amiga. the Paula chip might not have the C64 SID chip’s ring modulation and filter effects directly, but you can achieve similar results through clever techniques:

• Combine two channels for a 14-bit waveform
• Modulate one channel with another (amplitude modulation/AM)
• Chain channels modulating each other, producing results very similar to FM synthesis

This homebrew track demonstrates the last kind of modulation and sounds remarkably close to FM synthesis despite using purely sample-based hardware.

One rarely used trick (seen in the homebrew game Motorola Invaders 2) was to re-sample several channel tracks into one channel to give the illusion of using more channels. This is more akin to streaming a full song like in several later Neo Geo games, or indeed some earlier Amiga games, though those used shorter loops or only played the music outside of the game itself. The downside is less flexibility, but it allows for very dense arrangements and playing back recorded music.

Audio Cues as Gameplay Guidance: Part 2

Gauntlet (ARC, 1985) - The stat upgrade potions in this game last until you use a credit or they're stolen by thief enemies, which appear in some later levels in the game. You are warned by an audio cue when a thief enters a level, giving you a chance to hunt them down before they steal your hard-earned upgrades. It's a simple but effective use of audio to convey important gameplay information.

Mind Walker (AMI, 1986) uses audio in a fascinating, ahead of its time way. The second track in its OST, playing in the top down maze segments, is a kind of ambient noise made up of a beat and a sustained note with a guiding function. It speeds up and climbs in pitch as the player gets closer to reaching the goal of the maze. Similar to the earlier Dungeons of Daggorath, it creates tension while helping the player.

It Came from the Desert (AMI, 1989) - This adventure game features an audio cue in the form of a strange oscillating noise before a giant ant appears. While this is just for dramatic effect rather than for finding or avoiding the ant, it effectively builds tension before encounters, contributing to the game's B-movie horror atmosphere.

Dungeon Master (PCs, 1987) - In this seminal real-time, party-based dungeon crawler RPG (Blobber RPG), stereo audio cues indicate when a nearby gate is closing or opening, and you can hear nearby monsters moving around as well.

Prince of Persia (AII, 1989/PC DOS/AMI, 1990) - The game that invented and popularized the cinematic platformer subgenre features some gameplay guidance via audio cues in that opening and closing gates make a sound that can be heard outside of the screen/room they’re placed in, and when opening the exit gate to a level the game plays a jingle.

Finally, in Airborne Ranger (C64, 1987/PC, 1988/AMI, 1989), an early Stealth/Tactical Shooter game, you can hear enemies coming before they enter the screen. And in the ARPG Zeliard (PC-88/Sharp X1, 1987/PC DOS, 1990), there's noise outside boss rooms as a warning (just like in The Legend of Zelda).

Speech Synthesis on the PC-88/98 Computer

The Yamaha YM2203 (OPN) chip, used in Japanese PC-88 and PC-98 computers, wasn't designed for speech synthesis any more than the OPL2 was. But that didn't stop developers from trying! Silpheed (PC-88, 1986) and Zeliard (PC-88, 1987)feature speech synthesis that, while robotic and somehow squelchy sounding, adds personality to the game. This was achieved through the chip's CSM (Composite Sine Modulation) mode, a feature rarely exploited by developers.

Diegetic Music: When Game Music Becomes Part of the Game World

Most game music is non-diegetic - it exists outside the game world for the player's pleasure or to elicit an emotional reaction. But some games experimented with diegetic music - music that exists within the game world itself and can be heard by the characters - even early on in game history.

The Bard's Tale (AII, 1985/Multi, 1986-1987/NES, 1990)(1987 Apple IIGS ver. linked) - In this first-person view RPG with turn-based combat, a bard character equipped with an instrument can play songs, functioning much like magic spells. If played outside of battle, they also become the background music to your adventure. The game is otherwise mostly silent on PCs, making these musical moments stand out. Besides that, the intro cutscene, and party creation screen also feature diegetic music, played by an NPC in a tavern.

Maniac Mansion (PCs, 1987/NES, 1988 JP & 1990 US) - Features some diegetic music when characters play the piano, which is used to solve a pretty intricate puzzle by recording it onto a cassette tape. This element adds to the game's sense of place and makes the game stick with you.

It Came from the Desert (AMI, 1989) - This one includes diegetic music at the radio station and via the radio in the pub. While NPCs don't really react to it, it really helps establish the smalltown vibe the game is going for.

And there you have it. From interactive music systems to software synthesis on sample-based hardware, from speech synthesis on FM chips to diegetic music that blurred the line between soundtrack and game world, this period saw composers and programmers pushing boundaries in every direction. None of this had to happen, and for most games, it didn’t. These were all early experiments, not yet industry standards that players expected from games. Storage was tiny, deadlines were brutal, and every kilobyte spent on an extra instrument or sample was one you couldn’t spend on another sprite, level or dialogue scene.

Yet the composers, sound designers and programmers for the games covered here made the choice to go that extra mile, and you can trace the influences on much later games from these earlier days. Software synthesis on the Amiga predicted modern virtual instruments. Diegetic music in The Bard's Tale and It Came from the Desert planted seeds that would eventually grow into games like Bioshock and the GTA series, where in-world radios and jukeboxes became crucial tools of immersion. iMUSE’s vision of music responding seamlessly to gameplay would eventually be realized in games like Red Dead Redemption 2 and God of War (2018), just two decades later. Even now, when we have essentially unlimited audio capabilities, the creative problem solving from this period remains instructive and inspiring.

Thanks for reading!