The game may be fictional, but the numbers are certainly real: $800 million in sales in one day, 13 million copies sold in 24 hours, a billion dollars earned in three days. Rockstar Games' GTA V immediately celebrated the highest-earning video game launch in history after it dropped September 17, with everyone from Danny Brown to Tyler, The Creator reveling in the release.

But those aren't the only striking numbers that rolled out as the game spread across the world: 241 songs, 17 radio stations and the series' first-ever score created by a team of four producers working with Rockstar's three-man music department all went into the massive and detailed soundscape that makes up the game's nuanced aural experience. In addition to German electro pioneers Tangerine Dream and seasoned composer Woody Jackson, Rockstar Music Supervisor Ivan Pavlovich tapped The Alchemist and Oh No, the producers who together make up the duo Gangrene, to help map out the sounds of Los Santos' fictional L.A., marking the first time the game would include an original score in addition to its tried-and-true radio station-based musical formula.

"The first thing we all had to remember, the most important thing, was to make sure the experience of the radio stations remained the same as all the other GTAs," said Pavlovich in a phone interview with XXL. "And then the purpose of the score is really to support the narrative and action of the game without ever getting in its way. Our goals were set really high for this game—we wanted to go and create as much original content as we could for the various radio stations. So we started reaching out to all of our friends, especially fans of the game."

Two of those friends were Alchemist and Oh No, who had previously worked with Rockstar on Chinatown Wars in 2009. Rockstar reached out to them more than a year ago—Pavlovich and his team, comprised of Tony Mesones and Jaesun Celebre, had been working on the game for a year by that point—and asked them to contribute. But the two worked mostly in the dark, making beats based on vague descriptions before tweaking and tightening them according to mission details as the process moved on.

"We know how Grand Theft Auto plays out, we know what kind of music we would want to hear towards that game, so we kind of went off that," said Oh No in an interview with XXL. "They would give us descriptions of certain missions, and we would just make music towards where they were going with that."

"We were locked in for the whole year," added Alchemist. "The other projects we were doing, we were sneaking off and getting work done. And obviously not using any samples for the game was another challenge, too, jumping through that hula hoop... We didn't see anything until probably three-fourths of the way in."

Together with Tangerine Dream and Jackson, Al and Oh would take their original beats and craft what would become the background to the multifaceted game itself, the soundtrack to the car-stealing, store-robbing and various other illegal or semi-legal activities tasked to the many characters of GTA V. But that was just one aspect, as Pavlovich pointed out—the radio stations are a staple of the series, and the latest were the largest and most complex the franchise had ever compiled.

"This time we've had more original songs than we've ever had in the past," Pavlovich said, noting that people like Tyler, The Creator and Flying Lotus were really excited to work on original music for the game. "The different characters need soundtracks, the different environments need soundtracks, so the radio stations that ended up being in the game reflect all those different situations in the game."

One of the biggest guidelines, music-wise, in GTA V was the game's return to Los Santos, Rockstar's fictionalized Los Angeles, which helped to steer the radio stations in a distinctly L.A.-centric direction. "Whether it was classical radio or contemporary hip-hop radio, we wanted it to be reflective of Los Angeles and the music scene in Los Angeles," said Pavlovich about the radio stations. "Whether it's the classics or whether it's the new artists and the up-and-coming artists. That was our mission: to be very faithful to what is being played in Los Angeles and the music that is coming out of Los Angeles."

"I rode around in a low rider for a couple weeks," laughed Alchemist when speaking about the L.A.-tinged score. "Felt the vibe, went to the L.A. river, just rolled for a little bit, just to capture the essence."

"We definitely had to bring some West Coast vibes to it," added Oh. And the hip-hop that made it onto the resulting soundtrack is representative of that: Snoop and Dre, Tyler, Flying Lotus, Problem—much of the music comes directly from the source and is representative of a lot of the deeper cuts from the area's rich musical history.

"We spent a lot of time internally with our teams researching," said Pavlovich, adding that he's been listening to a lot of L.A. hip-hop. "Our record collection is amazing right now."

And the people seem to be responding. The game was always going to sell well—it was the first GTA in five years, after all—but the critical reception has matched the fan response. "I think it's getting what it deserves," said Al. "We're back doing our own thing, but it was definitely a good opportunity for us." —Dan Rys (@danrys)