Warning: This post contains minor spoilers for Stranger Things' first season.

AUSTIN, Texas—If you close your eyes and think about Netflix's hit, Stranger Things, what immediately comes to mind?

Chances are, it's the 54 seconds of pulsing synthesizer embedded above. That's the handiwork of Austin musicians Kyle Dixon and Michael Stein, half of the all-synth band S U R V I V E and composers for the show.

The Stranger Things sound has become such a phenomenon that the original soundtrack landed on the Village Voice's annual Pazz + Jop poll of music critics for 2016. So when the duo sat down to record a live podcast with Spotify during South by Southwest, the question was simple: how does it feel?

"It doesn't feel bad," Dixon said. "Maybe it's a bit bizarre. We've done music like this for a while, but people now care more."

"We also don't have to explain the band anymore," Stein noted. "We can just say, 'have you seen Stranger Things?'"

Since Netflix debuted the series in summer 2016, S U R V I V E had the opportunity to play live shows solely of Stranger Things music (Moogfest 2017 will be the last chance to see that for a while). The band's profile has been elevated to the point that Dixon and Stein will be headlining Coachella as counter-programming to Lady Gaga this year. While perhaps that level of success wasn't predictable, show creators the Duffer Brothers envisioned a show where music mattered.

"The Duffers actually pitched us the show by saying they wanted the music to be something people talked about," Dixon said.

"Scores can often get washed in and lost beside the mood they set," Stein replied. "But these guys wanted the score to be something."

Apparently, the Duffers stumbled across S U R V I V E on Spotify. Dixon and Stein said a sync (having their music placed in a TV or film soundtrack) from their 2012 record caught the showrunners' eyes. Everything sped into motion from there.

"They e-mailed us to ask if we were still a band," Dixon said, noting perhaps S U R V I V E took it a bit easy in terms of formal records at the time. "When we saw 'Netflix, sci-fi, and Winona Rider,' we knew."

Stein and Dixon started off by working from character bios and descriptions sent to them from the Duffers. They composed much of the show's music library even before seeing scripts (and long before seeing images). Ultimately, Stein said the duo composed more than 13 hours of stuff (yes, the series' official run time doesn't even match that). And during their SXSW chat, they walked everyone through the thought process behind three notable sounds.

The upside-down

At first, Stein and Dixon tried composing a traditional song to work as the upside-down theme, but something about it felt "off" to the duo. "With the horror scenes, we found noisier and more abstract worked better to get the scares," Dixon said. "Take that versus a '70s horror that might emphasize a scary scene with funk bass. It's laughable now. A regular S U R V I V E track sounded too cheesy."

The passages highlight Dixon's point. To me, that upside-down feeling starts roughly at 2:20 in the video above. The tone shifts, and the striking quarter note "melody" gets punctuated by these booming, da capo-style notes that hit like cannons. Stein and Dixon said that point represents the emergence of the demogorgon. The overall track brings you through the creepy and ethereal upside-down in a moment of tranquility.

"That's not a note—it's microtonal," Dixon said, regarding the demogorgon moment.

Let's geek out for a moment. If you've been raised on music from the Western hemisphere, you think of it as being built from the same 12 semi-tones, whether you know it or not. Twelve half-steps separate middle C from the next C. But, for Stranger Things, S U R V I V E grabbed irregular intervals—i.e., pitches that don't exist in Bach, Beethoven, and Radiohead, unless a guitarist does a bend—but might exist in India and China. "That gives it an uneasy feeling against the main melody. Then those 2600 big bass hits show up, so it's not very musical. But it's more effective than a regular melody."

"The upside down is weird and experimental, and we approached it with something like the Alien soundtrack," Stein added. "But this music focused on the monster."

Note that when Stein and Dixon refer to the 2600, that's an ARP 2600. It's a vintage semi-modular analog synthesizer, perhaps most recognizable for creating the booming space sounds in the original Star Wars. Both Stein and Dixon grew up collecting synthesizers, and they continue to mix classical instruments with modern synths in their work (Stein even worked in a famous Austin synth store so he could get first dibs on machines and learn to take 'em apart).

Eleven versus the bullies

Stein said S U R V I V E doesn't usually make music the duo would consider whimsical or happy. But large stretches of Stranger Things' season one focuses on a group of kids having fun and embarking on adventures, so the show pushed Stein and Dixon beyond their comfort zone. Eleven's theme is a good example: it's sparse and soft, with a sustained synth laying a quiet foundation for a delicate melody. "It's a music box that's a little sad and introspective," as Stein put it. The sound reflects the character's reality, as Eleven is initially a scared kid in a new environment where she feels vulnerable.

That said, Stein and Dixon manage to create a few moments that would be at home on the latest S U R V I V E record. "Eleven's cowboy heroism is the closest thing to a S U R V I V E sound in the entire score," Stein said. It's loud with moving synth lines and big, booming notes that demand attention. (S U R V I V E typically plays live only as a synth quartet: "An indie band may have one synth player playing a cute melody," Dixon said. "We wanted to see an all-synth band on stage playing loud; we hadn't seen that.")

In the same way Eleven's theme supports what the character is going through when being introduced; this moment of heroism is reflected within the musical cue. "This passage is a big triumphant song, and we also used variations of it when Winona axes the wall [finally understanding where her son is]," Stein said. "In those moments, you need something heavy and driving."

Eleven versus the demogorgon

The last cue Stein and Dixon discussed happened to be one of Stein's favorite moments in the entire first season. Musically, the duo noted the sound is actually similar to the soundtracking during Eleven's big western-style duel scene.

"That chord progression [from Eleven versus the bullies] is similar," Dixon said. "Against the monster, it's ambient: no drums, maybe a bit more sentimental. But it's fundamentally the same song."

Initially, the composers thought they'd have to reflect the chaos happening on-screen: the kids are seemingly doomed, stuck in a room with this indestructible monster that's already ransacked the entire school. But opting for something more akin to the demogorgon sound didn't quite fit.

"We found you can showcase the emotion stronger by using something running counter to what's on the screen," Stein said.

"Yeah, the visuals are so intense, this ended up being more effective than firing off audio gun shots, so to speak," Dixon added. "You're supporting the show and the action going on by not establishing a full five-part song."

"Something so sparse can be so powerful on-screen," Stein concluded. "But if you release the same thing disconnected from the show... "

"They'll think you fell asleep on the keyboards," Dixon said.

Dixon and Stein wrapped their chat by noting they're already working on the sound for season two. Although they were understandably hesitant to give any spoilers, they reassured everyone that S2 will have that familiar feeling.

"There are new characters, fun, and the upside-down will be more of a place—you'll spend more time," Dixon said. "So we'll make a lot more weird music this time around."

Look for more from Dixon and Stein's SXSW chat during an upcoming episode of Showstopper, Spotify's original podcast about music in TV and film. It's hosted by Fader Editor-in-Chief Naomi Zeichner, and it's available in both the free and premium versions of the app. Stranger Things S2 debuts on October 31, 2017.

Listing image by Anna Armatis / Netflix