The Sound of the Machines
Game Boy
Four channels. One note at a time. And the trick that made one channel sound like three.
DMG-CPU (built-in APU) 4 channels · Nintendo · 1989
The Chip
The Game Boy carried its sound hardware inside its main processor chip. There was no separate audio chip. The sound unit was built into the same chip that ran the game, and it shared that chip's small budget of processing power. Four channels. That was the entire sonic world of Game Boy music.
One of the people who built that sound unit was Hirokazu Tanaka, a Nintendo sound designer who had joined the company in 1980. About five or six people at Nintendo worked on the Game Boy hardware. In 1989 Tanaka was also writing the music for Super Mario Land and Tetris, two of the first games for the machine. He says: “Back then, I was composing and programming at the same time. I was designing the sound inside the Game Boy console as well.”
Nintendo wanted a machine smaller than the Famicom that did not cost more. He says: “The precision of the sound would be compromised, but I still wanted to create richer sounds than the Famicom.” The Game Boy had a headphone jack. He says: “The Famicom didn’t have stereo sound, but I found a way to force the sound out from the left, or right, or both.”
Two of those channels played square waves — electronic tones with a buzzy, slightly nasal quality that is immediately recognizable as "Game Boy sound." Each could be set to one of four duty cycles, which changed the timbre slightly: thin and metallic at 12.5%, rounder and more hollow at 50%. These two channels typically carried the melody and whatever harmony the composer could fit. One note at a time, each. No chords. No simultaneous voices.
The third channel was unusual. It held a table of 32 values that described a waveform — whatever waveform the composer chose to draw. Smooth and flute-like, or aggressive and sawtooth-sharp, or something in between with no name. Channel 3 was the most flexible voice on the chip: the one where the composer's own sound design decisions were most audible.
The fourth channel was noise — a generator that produced random-frequency signals useful for drum sounds and percussion textures. Short noise bursts gave something close to a hi-hat. Longer noise, lower-pitched, approximated a snare. Tanaka says: “With regard to the Famicom, there was only one kind of noise to use. But with the Game Boy, you could choose between two kinds of noise. There was the original noise wave, and a more cyclical noise that sounded like a ‘beep’ sound.” Between those four voices, every piece of Game Boy music ever written had to live.
Tanaka talked about the finished machine in 2025, at the BitSummit game festival in Kyoto. He says: “…the original Game Boy supposedly has the best sound of all. That’s what people say. And the reason for this is because we put a lot of thought into tweaking the way the machine noise sounds, and adjusted the way the amp works a little bit as well, so that really helped to change it.”
In February 1996, Game Freak released the first Pokémon games in Japan: Pokémon Red and Pokémon Green, sold abroad as Red and Blue. Their music came from Junichi Masuda, working with the same four channels. He says: “We’d write music directly on the Game Boy using a special device. For those games, I wrote all the songs and created all the Pokémon cries.”
Channel reference (technical)
Tomita's Track
Miracle of Four Voices
What to listen for
This piece was designed to let you hear the arpeggio illusion in the moment it happens. For the first eight bars, only a single melody plays — one channel, one note at a time. Then at bar 9, Channel 2 enters and begins cycling through the three notes of a C major chord faster than your ear can separate them. Listen for the moment the single stream of notes becomes what you hear as harmony. You are not hearing three notes. You are hearing one. Your brain is constructing the rest. The piece is built to make that construction visible.
The Game Boy has two square waves, one wave memory channel, and one noise channel — four channels in total. I gave Channel 2 two jobs at once: fast arpeggios for harmony in even bars, bass plucks in odd bars. The staging — one voice entering at a time — was not a compositional style choice. It was the only way to make the arpeggio illusion legible: you need to hear the one-channel version first so you can feel the moment it becomes a chord.
The real story this piece is built on
DMG-1: The Game Boy's two melody channels each play one note at a time. Composers discovered that cycling through chord notes faster than the ear can separate them — roughly 16th notes at 100 BPM or above — creates the illusion of simultaneous harmony. This 'fast arpeggio' technique is why the Tetris theme sounds richer than four channels should allow.
How this piece was made
This piece is designed to let you hear the trick being played on your own ears. For the first eight bars, only the melody plays — a single line, one note at a time. Then at bar 9, Channel 2 enters. It is cycling through C, E, and G at 16th-note speed — 95 BPM means those notes are switching about six times per second. What you hear is not three separate notes. You hear a chord. One channel, three perceived voices: that is the arpeggio illusion Game Boy composers used with only four channels total. I built this piece specifically to make that moment audible — the instant when a single stream of notes turns into what your brain calls harmony. At bar 17, the bass and drums arrive and the fourth channel joins. All four voices, all four channels, all working at once. The constraint is not hidden. The constraint is the point.
Techniques used in this track
- CH2 fast arpeggio at 16th-note speed: C → E → G → E cycling faster than the ear can separate — your brain hears a chord that does not technically exist
- CH1 lead melody (50% duty square, medium decay): single notes that feel stable against the arpeggio underneath
- CH3 wave memory walking bass: a custom waveform — the one channel that lets you design the shape of the sound itself
- CH4 snare (cs=3, 15-bit LFSR) + kick (cs=5): tested six settings, chose the one that felt closest to a real drum hit
- Staged voice entry: bars 0–1 melody only → bar 2 arpeggio enters → bar 8 bass and drums arrive
- The staging is the thesis: you hear the illusion being built one layer at a time
- Bar-by-bar variation in the bass pattern: avoids repetition, keeps the piece alive across its 17 bars
Three things about the DMG audio chip
The tricks below were used by Tanaka and by the many composers who wrote for the same four channels after him. Here is what that hardware made possible.
Four channels that cannot play chords — and the trick that made it not matter.
The Game Boy's two main melody channels each play one note at a time. A chord needs several notes at once, so two channels cannot play a three-note chord. The answer was speed. If one channel switches between the notes of a chord many times a second, the ear stops hearing separate notes and hears a chord. This is called a fast arpeggio. Tanaka had used it on the Famicom before the Game Boy. He says: “You were limited to three channels, so there was a lot of trial and error. For instance, you had only three channels, but if we ran them like high-speed arpeggios, it would sound fuller. We came up with a lot of little tricks like that.”
Channel 3 let composers design their own instrument from scratch.
The Game Boy's first two channels produced square waves — a fixed waveform shape that produces a characteristic buzzy, electronic tone. You could choose the duty cycle (the width of the wave), which changed the timbre slightly. But the waveform itself was fixed. Channel 3 was different. Called the "wave memory channel," it held a table of 32 values that described any waveform shape the composer chose. A perfectly smooth sine wave, soft as a flute. A sharp sawtooth that climbed fast and fell off a cliff. Something in between, with custom overtones no standard waveform had. The sound of Channel 3 was entirely a design decision — not a parameter in a menu but a shape drawn from scratch. For composers who understood it, Channel 3 was the most individual voice on the chip: the one that sounded like themselves.
The Game Boy was discontinued in 2003. Musicians were headlining concerts with it in 2006.
In 1998, Tanaka put a music maker into a Game Boy product himself. The Game Boy Camera came with a small music sequencer he built. He says: “For me, it was like I was revealing to everyone through this sequencer how to make this thing play music. Rather than showing what I could do, I wanted to share with others how much fun it could be.” Two years later, Swedish programmer Johan Kotlinski released LittleSoundDJ, or LSDJ. It ran from a cartridge, took over the Game Boy's sound hardware, and gave players a full music sequencer controlled with the Game Boy's buttons. By the mid-2000s, chiptune musicians were playing Game Boys as their main instrument at concerts, festivals and club nights. The Blip Festival, which began in New York City in 2006, brought performers from Japan, Europe and North America together, all playing Nintendo hardware that was no longer being made.
What four channels teach
There is something clarifying about working with four channels. The Famicom had five, the Super Famicom eight, the Mega Drive ten. The Game Boy had four. That is the fewest of any of the machines in this exhibition — and yet the music that came out of it is among the most immediately recognizable and emotionally direct.
When you cannot layer sounds, every note has to mean something by itself. When you cannot add reverb or chorus or a fifth channel to fill empty space, the empty space has to be intentional. The Game Boy is a machine that enforces compositional honesty: if you do not know exactly what you want to say, four channels will not cover for you.
The composers who understood this best — who learned the arpeggio trick, who designed their own waveforms, who let the four-channel budget be a discipline rather than a handicap — made music with a directness that larger, more complex hardware rarely produces. The Game Boy did not limit their expression. It demanded that their expression be precise.
Four channels is not a limitation. It is a question the hardware asks every composer: which four voices matter most? The ones who answered clearly made music that is still playing, decades later, in millions of heads.