Pac-Man · Arcade · 1980 · Action loop · Toshio Kai
The chattering two-note loop that plays as Pac-Man eats dots was built by Namco sound designer Toshio Kai from rapidly alternating square waves — an imitation of a mouth working, assembled from the only materials a three-channel sound chip could offer.
Toshio Kai composed Pac-Man's music and designed its sound effects in 1980, working on Namco's custom arcade hardware: an 8-bit CPU and a sound chip with three channels. There was no capacity for a recorded sample of chewing, and no synthesiser subtle enough to imitate one. Kai's solution was to alternate rapidly between two square waves at different pitches, producing a fast, repeating two-note chatter that the ear readily interprets as a mouth opening and closing. The effect loops continuously for as long as the player is consuming dots, which means it is not a discrete event sound at all but a state indicator — it tells you, without your having to look, that you are still eating, still scoring, still moving productively through the maze. That continuous quality is why the sound became the game's signature. A Pac-Man cabinet in a crowded arcade announced itself across the room by the waka-waka, and the sound entered popular culture under a name no designer chose: players heard "waka waka" in the alternation and the onomatopoeia stuck permanently. Kai arrived at one of the most recognisable sounds in entertainment history not through sophistication but through a precise reading of what two square waves, switched quickly enough, could persuade a listener to hear.
The constraint Kai faced in 1980 was absolute: three sound channels, no samples, no room for anything elaborate. Depicting the act of eating was therefore not a matter of recording or synthesising a chewing noise but of finding something within the chip's vocabulary that a listener would accept as one. His answer — two square waves alternating fast enough to read as a single articulated sound — works because the ear is doing most of the labour. Rapid alternation between two pitches is what a mouth does, acoustically speaking, and the brain fills in the rest.
This is the fundamental move of early game sound design, and Kai executed it about as cleanly as it has ever been executed. He was not trying to reproduce reality with insufficient means; he was identifying the one perceptual cue that carried the idea and delivering only that. The result costs almost nothing computationally and is unmistakable after a fraction of a second.
Most famous game sound effects mark events: a jump, a death, a coin. The waka-waka marks a condition. It runs for as long as Pac-Man is eating and stops the instant he is not, which makes it a continuous readout of the player's progress delivered entirely through audio. A player navigating a maze while watching four ghosts does not need to check whether dots are being consumed; the sound is already saying so, and its absence is immediately informative.
The consequence for the arcade floor was commercial as much as functional. A machine that emits a distinctive, near-constant chatter advertises itself to everyone within earshot, and Pac-Man's audibility across a noisy room contributed to a cultural ubiquity that a quieter game would not have achieved. Players named the sound themselves — "waka waka" is folk onomatopoeia, never a Namco term — which is perhaps the strongest evidence of how completely a two-note square-wave loop had lodged itself in the public ear.