YOASOBI's songs sound impossibly complex: bright piano melodies stacked over electronic beats, unexpected sonic turns, and ikura's voice threading through dense arrangements that seem to defy the limits of human breath. Yet the technology behind this maximalist pop is deceptively straightforward.

Ayase, the duo's producer, built his approach during his teenage years exploring Japan's Vocaloid scene, where a laptop and voice-synthesis software like Hatsune Miku let one person handle composition, production, and vocals. When he began working with ikura, her human voice replaced the synthesizers, but Ayase's ambition for intricate arrangements didn't shrink. His melodies often sound written without worrying whether a human can actually sing them—and ikura proves she can.

As YOASOBI has grown larger, Ayase's toolkit has become leaner. When asked to name five essential pieces of technology, he struggled to come up with a fifth.

The setup includes Logic Pro, where Ayase assembles everything; Splice, which gives him access to a vast sound library; a high-end Sony microphone for recording ikura's vocals; and wired EarPods—not AirPods. The wired Apple earbuds, increasingly rare in the AirPods era, remain essential to his workflow. Ayase uses them not out of nostalgia for the headphone-jack days, but because their relative simplicity serves him better than expensive studio speakers.

There's no mysterious piece of gear that creates the YOASOBI sound. Most of what Ayase uses is available to anyone with a laptop and an internet connection. It's what he does with the tools—not the tools themselves—that makes the music unmistakably his. The approach mirrors the production philosophy behind "Idol," the Oshi no Ko theme that has accumulated over 688 million YouTube views while ricocheting between musical ideas with little regard for pop convention.