Pokemon X/Y, which is likely to go down as Nintendo's top-selling title of 2013, is a real evolution for the series - not just the obvious ones, like the 3D visuals, but in a lot of under-hood aspects. Case in point: The sound system, which uses streaming audio for the first time in the main Pokemon series and required a near-total reinvention of the sound creation process.

Longtime composer Shota Kageyama was sound director for X/Y, taking over duties from Junichi Masuda (who handled general director duties in this game, although he also contributed a few musical tracks). "In making Pokemon," Kageyama told Famitsu magazine, "we always place a lot of emphasis on the reasoning and meaning behind 'why' you decide to do something the way you did. I used to rely on Masuda a lot, asking him 'What do you think about this?' and so on, but here I had to take responsibility for myself. I had to start by analyzing all the music in the series and reminding myself of why it's the way it is, then write a report for Masuda on how I think the sound should work, what direction it should take."

It's well-known that X/Y's Kalos region uses France as a motif, but that's not necessarily the main motivation behind the soundtrack. "Beauty is an extremely important keyword throughout this title," Kageyama said, "and I thought of assorted ways to express that in music. I worked on music while coming up with tones and melodies that I thought provided a design that evoked beauty in the minds of people. It's not that there are no French aspects to the music, but I'd never just put music from that region into the game, even if that's the motif. Pokemon is a fantasy world, after all, so I pay close attention to maintaining that gap from the real world."

"If you're at a chic cafe eating macaroons and you hear accordion music, that's the full French image, isn't it?" added Masuda. "But if you use, say, the koto instead of an accordion, that creates a more unusual landscape. I think we need to keep that sort of freshness to the feel; meanwhile, we're free to use the accordion for very non-French parts. Retaining that kind of balance in every aspect of the game is part of the Pokemon formula."

X/Y also sounds different from previous Pokemon titles in a slightly more subtle way: Kageyama and crew re-recorded all of the Pokemon cries for this game. "Once we decided to go 3D with Pokemon," said Masuda, "I figured it was also time that we changed up the kind of electronic-sounding cries that a lot of the Pokemon had. Something fresher and more animal-like to go with the improved hardware."

The power of the 3DS hardware was one reason for the move, but as Masuda explained, another strong motivation was the influence the Pokemon cartoon had on the minds of fans. "The cartoon's been on the air for 16 years and is shown in 83 countries, but everywhere you go, it's always Ikue Ohtani's voice for Pikachu," he said. "You can go all around the world and ask people what Pikachu sounds like and it'll always be the 'Pi-kaaa!' from the anime. I figured that, if that's how people see it, then that's how they'd probably like the game to be, too. So X/Y has a lot of changes, definitely."

"The process wasn't without some level of nervousness for me," Kageyama added, "but I think it was a pretty great idea, especially with this being a worldwide simultaneous release. Still, there's something like 3000 or 4000 voices overall used in Pokemon-Amie, which I tell you was a huge pain to do. Just recording all those cries was an enormous process."

With even a Pokemon game being a project that involves hundreds of people and several years to complete these days, it was often difficult for Kageyama to see the forest for the trees. Still, he's proud of his team's efforts. "With the Nintendo 3DS, the sound's gotten a lot prettier, a lot more dynamic, and a lot more real," he said. "It's far more expressive than it's ever been, and I think it's a real evolution, something you'll definitely want to take out the headphones for."