Considering the fact that most professional audio tools are democratized these days, developers everywhere are given new options for complex sound. Various layers of a boss encounter theme might fade in and out over the course of the battle. Things like footstep sounds can now randomize and alter for shifting environments. Many of the boundaries that prevented these features from appearing in games without insanely high budgets are now lifted.
However, many indies today still opt for extremely finite development tools that lack support for a large number of those techniques. Their few available resources and other limitations provoke a sense of creative problem solving. Because of this, we’ve seen a huge influx of releases that harken back to even the most early arcade machines. While trying to find ways these retro-style games can still be sonically interesting, a look to classic titles could give us some key insights.
The Adaptive Music of Dig Dug
A few weeks ago when I wanted something simple to play in bed, I grabbed my Game Boy Advance cartridge of Namco Museum. After scrolling through its library of oldies but goodies, I eventually found my way to Dig Dug. To my surprise, something stuck out to me that I'd never really given a second thought to before; the music stops when the character sprite is still, and then continues where it left off once the sprite begins to move again. It’s worth noting too that while the character sprite is still, the sounds of the creatures are brought to the forefront causing an unsuspected sense of ambience.
I came to the interpretation that this might’ve been implemented to encourage the player to continuously “dig” through the soil. After all, doing so not only adds points to your score, but it also forms canals. These canals can then be used to strategically take out groups of enemies at a time. Applying these kinds of simple adaptive music systems in games today can make even the most minimal worlds feel alive.
Responsive Sound Effects in Krazy Kreatures
Motivated to find more of these impressive feats in early game audio, I discovered a game far more forgotten in the pixelated sands of time known as Krazy Kreatures. Released on the NES in 1990 and probably never considered to be visually striking, this game still hides one shiny gold nugget in the audio design. The gameplay involves sorting groups of matching animals into rows to eliminate them from the screen within a time limit. A quick musical cue plays after each successful match.
The interesting thing here though is that the cue raises a musical key every subsequent time another row is eliminated. Even though this concept seems relatively simple, it delivers a massive feeling of accomplishment. With this in mind, we as developers might want to avoid using the same sound for repetitive actions. Instead, incrementing a set of cues that evolve in some way gives more feedback to our players.
A Link to the Past's Dynamic Ambience
After some further exploration, I returned to a game many more of us remember--The Legend of Zelda: A Link to the Past. While a ton of ground has been covered about this Zelda entry, I’d like to touch upon something rarely discussed. During the opening sequence, the series’ flagship character ‘Link’ awakens in his house during a storm. At this time, the only indication of the storm is a looping sound of rain. As soon as Link ventures outside, a loop that contains much higher frequencies replaces the previous one. This change emulates the same one our ears perceive when relocating from indoors to outdoors.
Even More Rain
A recent indie game to use this trick is one called Tea by developer Kyle Reimergartin. It begins similarly to A Link to the Past, with a character inside a house during a storm. Except instead of a warrior-child, the player takes control of a small frog. The rain sounds play at a certain register when inside the frog's house. Then while leaving the house, well you guessed it, the loop swaps with one in a higher pitch.
It’s important to mention that Tea was created in Pico-8, a self-described “fantasy console” that has recently been established as a staple among the indie community. It contains a holistic and accessible development kit but focuses on low resolution design. This limits the amount of feasibly possible audio systems, which makes dynamic sound in Pico-8 games a special rarity.
While these pioneering effects don't initially seem technically impressive, we see how they are still able to influence modern games. On top of this, I firmly believe that sometimes the simplest solutions are often the most valuable. So the next time you find yourself involved with making a game that uses a fairly concise amount of resources, you might want to dust off an old console or two and keep your ears open.