Function is one of the most electrifying DJs in techno. His sound is ominous and subterranean but also cinematic and expansive. Though mainly built from up-to-the-minute techno, his sets are never monolithic, particularly at Berghain, where he holds a residency. As he's drawing to a close near the four-hour mark—or, in the case of a closing set, just kicking into gear—he's prone to flashes of color that reveal the complexity of the dark hues he's working with. On more than one occasion I've heard him drop John Tejada's classic "Sucre" in the final stretch, and it feels like he's pulling aside the curtain to reveal there's a trickster pulling the levers on all the brooding techno. And even when he's right in the thick of it, playing his most menacing selections, he's usually doing so with a smile.Dave Sumner assumed the Function guise some 20 years ago in New York, where he held an early-'90s residency at Limelight, one of the era's most infamous clubs. But his roots as a DJ go back to his teenage years in suburban New Jersey, where his obsession with sharing great records with others really took hold. You could trace it further still to his childhood in Canarsie, Brooklyn, where disco, electro and freestyle records were blaring from every car that drove down the road. "When I was a kid and started hearing the music, I was fascinated with it," he told me. "It drew me in and took over my life. I really didn't have a choice."We spent an afternoon discussing his history and craft at his home studio in Berlin, where he made clear that all these years later, this same fascination continues to drive him in the booth.I had this almost magical experience when I was a kid. We lived [in Brooklyn] on East 80th Street—a big, really busy road—across the street from this members-only swim club. On Saturday nights they had these dance parties, but I wasn't old enough to enter. So during the summer, it was like a block party every weekend, and my backyard faced this swimming pool. The music was just radiating from across the street. At that time, hi-NRG, disco, electro, early hip-hop, freestyle—all these things were radio music. I get nostalgic when I listen to Intergalactic FM because it sounds like the soundtrack to my childhood.That's what caught my ear—it was continuous music. Later on, when I finally started DJing, I really didn't know anything about it. The turntables didn't even have pitch control. But I quickly learned.My sister's boyfriend at the time, when I was like 15 years old, he was a DJ—but he was just a bar DJ, and he had turntables at his house. He just didn't use pitch control, he was just going back and forth playing record after record, and I was fascinated by that. At the time I was recording a lot of mixes off Hot 103, which is now Hot 97. They used to do Saturday night dance parties, and I'd record the mixes and then talk about them with my sister's boyfriend. I'd go over to his house, play him stuff and be like, "Do you know what this record is?" I think for my 15th or 16th birthday, I got a mixer, just like a Tandy Radio Shack mixer. Within a few months I discovered Technics 1200s and then got this GLI PMX 9000, which was a really popular mixer at the time.You know, my mom had a lot to do with me becoming a DJ. At that time we were in Brooklyn there was a really strong sense of community, and my mom was very social. We'd always have parties at the house, so I quickly became familiar with entertaining people. And then later, when we moved to New Jersey, she wouldn't want us to go out and cause trouble. So we had this big unfinished basement, and she let me throw parties. I had a DJ setup, and my friends and I would cover the walls in graffiti and steal lights from construction sites.I've been reviewing things in my mind, and I've noticed that socially, this is the way that I've communicated with friends. The DJ booth was always a barrier—I was communicating with my friends through music. I had a nice little soundsystem, and during the summers I would play friends' parties. I was constantly loading stuff up in my car and bringing it to their houses, and I would be the DJ at house parties. So when I look back now, that was the way that I communicated a lot of the time. I was friends with everybody, but I wasn't really talking to them because I was just obsessed with playing music.My first was Joyce Sims,on Sleeping Bag. I think that was the summer of eighth grade, going into ninth. Growing up in New Jersey, there was a group of like ten of us who were all DJs, and we'd go over to each other's houses and show each other records. We all lived within a couple of miles' vicinity, and we all had DJ setups at our houses. If there was something I wanted, I would write it down and go find it.I don't actually remember the name of the club, but it was somewhere on the Jersey Shore. My sister's boyfriend at the time, he would play, and he took me along. It's sort of a distant memory, but I remember it not being very good [], and it was, like, a Wednesday night, mid-week. After that, locally in New Jersey I would play in Asbury Park at the Stone Pony, where Bruce Springsteen started getting his first gigs—that was 20 minutes from my house, so I was playing there often—and then a lot of crappy clubs in Jersey. I started going out to clubs in Manhattan, and then, eventually, started to play at Limelight.I'd say that I would ride mixes for longer back then. From disco into house music, New York was a rotary mixer town, like the Bozak, the Urei—these were staples.No, no—you would find normal up-and-down faders. But I'll never forget the first time I saw a rotary mixer. It was at Limelight, I was about to go on and I looked at the mixer and was like, "What is that?!" My hands were trembling. But after using it for a while, I came to realise it's really conducive to smooth mixing. So I think that rotary mixers lend themselves to riding mixes for longer.Stylistically things changed a lot in a very short period of time when I went from freestyle and house and then progressed to techno. In '91 or '92, the music style was changing so often. I remember going to Limelight when gabber started to surface—it was like every week the tempo was increasing, getting faster and faster until it got to 180. So in that the mixing style changed. There was a lot of cutting, and back then I used to use a crossfader—I would never use a crossfader now. And back then, I would cue up a record and throw the crossfader over completely to the other track, just to throw hints of it in very quickly.I had a residency at Limelight, but I was by no means one of the bigger DJs. I was playing on Thursdays, which was sort of the slowest night. The focus was Friday night—Lord Michael's Future Shock—and Wednesday night, which was Michael Alig's Disco 2000. On Thursdays, the promoter was always changing. I had a friend who was a promoter, George Picarello. We met at the club and would hang out. He wanted to hear me as a DJ, so he came out to my parent's house in New Jersey. He liked what I was playing, and I became his resident. I was like 18—it was a great experience to have at such an early age.There was one night at Limelight on a Thursday that made me realize that I was going to be doing this for the rest of my life. They were constantly moving the DJ booth around in the club, trying it in different spots. One night when I was playing, they'd set it up on the stage—Limelight had this really beautiful stage, a lot of music videos and live concerts were filmed on that stage—and Lady Miss Kier from Deee-Lite was there. It turned into a show, where she was dancing while I was DJing, just by herself on the stage. I was watching her music videos on TV, and now she's dancing for me. After a while, she came up to the DJ booth and whispered in my ear, "Thank you." We were driving home and all my friends were like, "What just happened?"On the radio, there were DJs like Glenn Friscia, Scott Blackwell and then on WBLS during lunchtime, Kenny Carpenter. I thought Kenny Carpenter was one of the tightest DJs I ever heard. There was Roman Ricardo at The Tunnel, Glenn Friscia at the Palladium. That was in the early days, when I was just finding out about things.When I really found myself as a DJ, it was Jeff Mills at Limelight and Adam X at Storm Rave. We don't really need to explain Jeff—I feel honored to have had him as a resident pretty much every Friday night for two or three years. That was like basically watching himJeff Mills. But Adam, I think in a way he had more of an impact on me, because there was something raw about the way he came across. There was a big illegal rave that I went to one time, and a lot of the DJs were playing music that I wasn't into—kind of early trance. Then this skinny little kid with a hood pulled up on his head walked up, and he opened with Mike Dunn, "The Pressure Cooker." It definitely changed my life. With Adam, it was really about selection. I mean, he owned a record shop and had access to records that nobody else did. He would play sometimes and we'd be like, "What record is that?" You'd go up to the turntable, and it's a white label, and on the record is written, "What are you looking at?"I've had this experience since I'm a kid—I'm pretty shy. At this point now, I can DJ in front of 100,000 people, but you could put a microphone in front of my face and I wouldn't say a word. This was a struggle for me in the early days, to get up there. And it was always a challenge, but it was something that I was so determined to get past. I remember sometimes driving into the city and just having a pit in my stomach. "How am I gonna get past this?"I felt like techno was more open than house music. House was very restrictive, especially in New York. And then I later came to realize that some of the records that I thought were house were also techno. I love house music, and I'm also a house DJ. I don't really like to say I'm a techno DJ or a house DJ, I'm just playing records—I like sharing music with people. That's ultimately what I've always wanted to do. I love being so obsessed with a track that I want people to hear it.I don't know, I guess it just felt honest and natural. Especially now that I look back at it. It was definitely a lot more personal. It was about learning, not only about being a DJ but about producing, sound, equipment and the process of making a record. Once I started DJing at proper nightclubs like Limelight I started getting incredible urges to create. And I didn't trust the educational system when it came to what I wanted to learn. At that time what I was looking to learn was on the outside, they didn't understand it. I went to school for music and production, and found they weren't teaching me what I wanted to learn. So outside of class I had to take it upon myself.I went to the campus library and took out books about synthesis and sound. Then started to buy and sell gear: modulars, drum machines and synthesizers. I worked at music shops like Sam Ash and Rogue Music. And then later at Europadisk, the famous pressing plant on Varick Street in Manhattan, as a production manager looking after accounts like West End, Salsoul and some of the Strictly Rhythm releases, among many others. I was also organizing a lot of events bringing in talent that wouldn't have been booked in the city otherwise. Artists like Mills (after his initial residency, around '99), Robert Hood, Claude Young, Surgeon, Regis, DJ Hell, etc. This was all between 1991 and 2001.It wasn't just about DJing—it was also production. There was a point, I guess 2000, 2001, where software started taking over. I was always producing on hardware synced up on a mixing console, just doing live mixes to tape. I was never really computer-savvy, so when things started heading in the direction of software, it took me a while to adjust. I was using things like Cubase and Logic, and it seemed a bit laborious.Then I discovered Ableton, and I started to realise that you could use Ableton not just for production but also for DJing. You could apply that time you would take away from matching beats to programming and remixing things on the fly. I was impressed with the way you could manipulate and get inside the music more. It sort of hit the refresh button, reinvented it for me. It was like starting over, and it gave me the same sort of excitement as when I first started. I did that for a while, like maybe eight years or so, maybe more.The Evolution UC33. Later I got the Allen & Heath K2s. Now my setup for live is laptop, controllers, 909, soundcard. And then DJing is three CDJs and a mixer.