I first heard of Silvia Kastel through her mixtapes. Knowing nothing of her background, I wanted to find out more about who was stringing it all together: electronic post-punk would seep into jungle via trippy computer music, with stopovers for dub, digi-dancehall and electro. Despite the heady content, the mixes didn't feel stuffy or self-indulgent, and their best moments were revelatory—the passage in Bibula Harena when shards of electronic data blend into warm jungle lingers in my mind to this day.

Kastel doesn't consider herself a DJ, but in the space of a few weeks I saw her playing electro for DJ Stingray, dubstep and jungle for Berlin bass institution Version and everything in between for Blackest Ever Black. Still, she's right to downplay this side of her musical life. Her past experiences have equipped her with a set of skills and values that are rarely seen in clubs. As both a performer and an audio engineer, she'd had a hand in over 20 releases by the time she started playing around Berlin.

Kastel grew out of a scene where the lines between free jazz, noise, industrial, sound art and all things extreme were fluid. From her late teens, she cut a stalking figure on stage as part of Control Unit, whose improvised sets pitched her voice and electronics against Ninni Morgia's guitar, resulting in impressionistic yet violent sonic duels. Barely 20, she founded Ultramarine, a record label that's released records by artists like Michael Morley and Smegma—hugely respected figures in the world of DIY avant-garde music.

When Kastel started working on her own, dank and sludgy electronics moved to the fore. Her background as a trained sound engineer and a regular improviser gave her an edge, and she eventually caught the ear of Blackest Ever Black, who are about to release Air Lows, an album unlike anything she's done before.

At the end of last year, I visited Kastel's home studio to get a sense of the process behind her new record. She described a desire to make "light and shade coexist rather than indulging in the darkness." Many producers in the so-called experimental corners of dance music take the opposite path, which is part of what makes Air Lows refreshing. It'll be many people's introduction to Kastel, but it's just the latest stage in a series of evolutions.

When did you first become interested in instruments?

When I was young, I messed around with a bit of bass guitar playing. My brothers played instruments but we weren't playing together or anything—I would just do it on my own. Then I moved to New York when I was 18. My partner at the time, Ninni Morgia, was a really good musician. I showed an interest in synthesisers and he was like, "Just buy one!" So I did.

And that's this Korg MS2000.

Yeah. It was my first synth and I've kept it with me ever since. Then the Tenori-on came out and I thought, "I have to have this." From there, I bought a lot of stuff over the years because we were both very obsessed with gear. Buying and selling all the time, it was our thing. But I didn't technically play an instrument. I studied piano when I was younger but I hated it.

The Tenori-on is fairly unusual.

Yamaha made it in 2007, and I bought it as soon as it came out because I fell in love with it. The sound designer is Toshio Iwai. He's an amazing, incredible sound designer. Maybe they didn't sell many of them, and I think there's a few reasons for it. It was too expensive, it's not easy to use, it uses a mini-jack and so on. It also looks a bit like a toy. There's in-built speakers and it looks like a Speak & Spell.

Is it a sampler or does it have a synth engine?

It's everything. The way you compose with it is extremely intuitive. It took me a while to learn but now I really like it. There are various modes for generating patterns but you can end up with percussion, synths, pads, whatever. Then, as a sampler, you modulate the sample length and the loop points by hand.

Is this on Air Lows?

It appears on the record but I'm using it constantly now, especially to start new ideas. It's also part of my live setup.

So you're in New York at a pretty early age and Control Unit becomes your first musical project soon after.

Yeah, I was in Brooklyn. Ninni is Italian but he had been living in America for several years before I arrived. Control Unit was initially just his project. He made a record called Ninni Morgia Control Unit with the free jazz sax player Daniel Carter and Jeff Arnal on drums. We were playing together all the time so we decided we needed a name. But we still liked Control Unit, so we kept it. Some people get confused when they see this record because you've got these players with a free jazz background grouped with the two of us, who had more of an industrial/noise approach.

What was your role in the group?

I was always playing synths, sometimes bass, making beats, singing, recording, editing. It was a great learning experience as a player and an engineer. I'd studied sound engineering, so I was already used to recording bands and friends. Getting comfortable with playing and performing took longer. It took years of playing shows and practicing. Singing was especially tough—I had to take lessons because I wasn't confident.

Do you look back on audio engineering school fondly?

I always hated high school and everything before. It was shocking that you could actually go to school for something you love. During that time, I interned in studios and worked in a lot of makeshift recording spaces.

I always find myself going back to what I learned in those days. It doesn't sound that relevant but knowing how to record a drum kit, for instance, or knowing how different mic techniques shape the hardness of a tone is still valuable. Understanding the architecture of sound, the way you can shape it and give it character—that's what I learned. Rather than relying purely on improvisation, it can help you arrive more closely at the sound you're hearing in your head. Of course, I learned a lot from improvising in the engineering process, too.

Given that you were mixing with free jazz players and artists from avant-garde backgrounds, was playing live and writing largely improvised?

I'd always start improvising. Obviously once you've been doing it for a few years, you begin to understand that you're looking for something specific. So now I always have a sound in mind and then I try and achieve it. Still, when you know your equipment well, improvising means you're working in very well-known territory. The instrument has its limits and you start to recognise your own tendencies within those boundaries.

Control Unit was literally us improvising for hours. Recording, overdubbing, dubbing tracks with effects, editing the structure and so on. In the last two or three years of the project, we were writing actual songs but we always kept the connection to this free approach.

These people from the general free improv, DIY world are prolific by definition—they can show up at some venue, record the session, then there's a record. You might play with a different group multiple times per week. It's very rare to find an equivalent context in electronic music.

To be honest, this is part of what dragged me towards electronic music. At some point, I was looking for more structure in my music. Ninni played with far more people than I did and was more of an improviser from an ideological standpoint. But I was getting frustrated with not being able to fix ideas as I wanted. Ultimately, I'm a sound engineer who loves to sit down and spend hours on a sound. So I was missing that.

The other thing that pushed me toward electronic music was going to clubs for the first time and hearing things on a big soundsystem. You know when you discover something you haven't really explored before? There's a sense of untapped potential, and learning about it all is exciting.

Did you get into electronic music while you were still in New York?

No, it was more recent than that. I wasn't listening to techno in New York. But when we came back to Italy, I started listening to the usual classic stuff, like Surgeon, Regis, Jeff Mills. I was in charge of the bass sounds in the group, so all these huge, pulsating sub frequencies really grabbed me. Ninni wasn't as into it and whenever I tried to push things in a faster direction in the studio it wouldn't work out. So I always repressed my interest in techno. Clearly I'm not making techno now, but the overall sound is much more electronic than before and there's a beat or a pulse. The point is that it was a very slow transition to where I am now.

You started your label Ultramarine in 2009 and almost immediately started releasing work from people like Michael Morley and Smegma. Those names might not mean much to a club music fan but they're hugely respected figures in the avant-DIY world. Smegma were even on the legendary Nurse With Wound list. You'd only been in America for a bit over a year, you're basically still a teenager—how did you make this work?

It's all quite simple really. Maybe in hindsight it seems impressive but these people are just friends and the idea to release something was very spontaneous. I saw Michael Morely playing as Gate, we had a chat, became friends. Then he showed me an album he'd recorded and it was as easy as saying, "OK, let's release it." Then with Smegma, we were on tour on the West Coast and stayed at their house for a few days and recorded in their bathroom. Then later, they sent me their album and I put it out. That's all there was to it.

How did you pick up the basics of running a label?

I didn't know. I just did it. I was using a fairly dodgy pressing plant in New York. It wasn't good but it was cheap. When I returned to Italy I switched to a much better plant, Elettroformati, which pressed the Smegma and Gate records.

I also noticed you're credited as mastering engineer on a Philip Corner record, another really significant figure in avant-garde circles.

Yeah, I mastered a few things for that label, Ricerca Sonora.

Why did they choose you instead of a traditional mastering engineer?

To be clear, I'm not a mastering engineer. They'd had the record mastered and Philip Corner didn't like it. Then they sent it to someone else and received another conventional master. Philip wanted to keep all the dynamics intact. He makes very specific music. So the label suggested me, on the assumption that I understood this musician's perspective on mastering. He liked what I did but I didn't have the equipment or experience to call myself an actual mastering engineer. It worked with Philip because I was very conservative with compression. I would never dare approach mastering a club track.

In this strain of avant-garde music that forms your background, the ethos of recording is about authenticity and documentation. Electronic music production is usually the opposite.

Yes, it's hyperreal—or unreal—in comparison. I find that a lot of music, not just electronic, lacks dynamics and character. I'm always looking for how I can make the sound more personal, less predictable, to give it a looser, live feel. I don't quantise stuff and deliberately push sounds off the grid where appropriate. It's not so obvious but on "Bruell" I wanted to simulate the washy, metallic sound of a free jazz drummer playing cymbals. This isn't special or unusual by any means, but these are the terms I'm thinking in.

Jungle and drum & bass have had a much bigger influence on me than, say, techno. Obviously my music sounds nothing like jungle but what draws me to it is a looseness and the clear sense of experimentation. The impossible drum breaks mixed with the half-speed basslines—you can feel they were just trying out crazy ideas. There's the same feeling in some early grime. You can't easily manufacture this energy but I try to have this kind of approach.

What was it like moving to Berlin and seeing all these techno DJs with four-figure booking fees after working with the cream of the DIY underground in the States, where legendary figures play for peanuts?

This is a good question because I think about it quite a lot. My identity is back there and I don't think I'll ever be able to fully change my mentality away from that approach. Sometimes I miss being surrounded by people who can't help but be constantly creative for no other reason but the love of it.

I was a bit naive before I moved to Berlin. I didn't know about the electronic music scene at all, what the conditions and opportunities were. It is much more professional than what I was used to, which is stimulating in its own way, but very different in practice. It was a bit of a shock, seeing that it's such a developed business when you never thought of music in that way. Being here made me realise, no matter how insignificant people are in the grand scheme of things, it's very much a hierarchy with people jockeying for position.

Meanwhile Smegma and Factrix are driving around the States sleeping on people's floors.

Well, yes, back when they used to tour. There's plenty of people doing it. We never had a hotel when we were touring. We'd be really happy on the occasions that we could sleep on a floor or in a motel. Also, this infrastructure of labels and agents really wasn't a thing. We made our own records, booked our own shows and made our own way on tour. Of course there are people doing this in the dance music world, too. And after a few years, it's nice to be rewarded for the hard work you put into something. I don't miss the harder life. It's just the people I miss.

Were the tracks on Air Lows made with a lot of channels? Sometimes it feels stripped down to just a few elements but the complexity of the atmospheres makes it seem like there's a lot going on behind the scenes.

I wish there were only a few channels! Now that I'm preparing to play the material live, I'm revisiting the old sessions and thinking, "Silvia, you are insane." The tracks can sound quite empty but there's a lot of layering, especially blending lots of reverbs with a few different kinds of delay.

The sense of space on the record is distinctive. Spatial effects often come across as generic but it sounds like you worked at having the space feel a specific way.

Especially the tracks on the B-side. I spent a lot of time on the reverb. This sounds so clichéd but I was asking myself, "What does the void sound like?" Obviously John Cage was asking this question and realising silence doesn't exist and so on. But I was thinking of how heavy so-called silence can be. Much heavier than a harsh noise sausage waveform. I was working with very quiet, tiny particles of sound and listening a lot, especially to the tails of reverb. It reminded me of improvisation actually because you're working so much with silence and waiting for something to suggest another sound to you. If you work with it in a certain way, quiet, empty space can be very heavy.

Your voice is another subtle presence on the record.

The vocals were hard to produce. I'm not sure why. Maybe because I was trying different microphones. You know how Sonic Youth released a series of records on their own label? Whenever Kim Gordon picks up the mic I am struck by how beautiful the tone of her voice is. This is what I had in mind but I also wanted to communicate a damp, underground space.

You don't really sing on Air Lows but I heard you used to push your voice to extremes. Could you tell us about taking workshops with Joan La Barbara? She's more or less the queen of extended vocal technique.

She handed us a pamphlet labelled "Joan La Barbara's Vocal Warm Up" and we'd go through a set of exercises with her, which consisted of yoga positions, breathing exercises and techniques for preparing your vocal chords. I could never do the overtone singing stuff, that was way too difficult.

Could you explain what that is?

Usually you sing just one note at a time but, with certain techniques, you can layer other pitches above or below that note. When she did it, it was almost like a low growl but it was harmonically perfect and in key with the higher tone. She's the most insane singer I've ever heard.

You released a tape of Voice Studies back in 2015. What were you doing with your voice there?

One side is me singing through a synthesiser and effects, looping and reversing it all live. The other side is just vocals. I did it in an empty room because I liked the reverb. It was untreated and had natural reflections, which gave a sense of space to these quite abstract, extended vocal techniques I was exploring.

After returning to Italy from New York, I was living in the countryside where I met a vocal instructor who gave me lessons in both opera and pop singing. Opera singing is completely different, the setup of the voice and the breathing it requires is very specific, like learning to play an instrument.

You've got all this technique but your voice is almost always obscured on Air Lows.

I always record and then sample, resample, repitch and so on, especially with the Electro Harmonix 2880 looper. It has four tracks and I can change the tempo and the octave, which means you can alter the sound quite drastically. I like reversing a single track and then blending the dry signal back in while changing the pitch. But the reason the voice isn't so prominent is that I wanted to use it like a brush, painting some light strokes here and there.

Why don't you sing live anymore?

This is another thing that changed when I shifted from being in a band to working on my own. I toured solo a couple of times, so I'd be singing, performing and playing the machines. Now I realise I'd rather sacrifice—for now—the performance aspect and play more. I had to choose between singing live and making a visually entertaining performance or focussing purely on what I'm doing in the music. My set includes visuals now, so there's a better balance of sonic and visual stimulation.

When you say "performance" here, you're referring to your stage presence, right? I never saw you play in this era but I heard you had a pretty physical, almost violent vibe on stage.

It depended on the show and the mood. But yeah, some shows I liked to fuck with the audience. Playing with a band, I was much more free to push things in this way. Alone, I can't do it. I see some artists who can and it's very impressive but I've tried many ways and it hasn't worked out.

I remember you telling me some time ago that you had finished a version of what became Air Lows but you decided to scrap it and start from scratch. What did the other version sound like and why did you start over?

I don't know if you know my release called The Gap—the first version of the album was similar but better produced. I was recording at a friend's really good studio in Miami with all these high-end reverbs and great outboard gear. I don't know, I guess I wasn't happy with it because it reminded me of my connection to industrial noise. The record wasn't bad, I just didn't want to continue with that aesthetic.

The first two or three times I listened to Air Lows I had to recalibrate my expectations. I really didn't expect someone from your background to make such a serene and colourful record.

I was kind of sick of performing as a noise artist. Sick of distortion, sick of how I was using my voice. When I'm on my own, especially playing with the Tenori-on, I make disgustingly poppy stuff. Not quite mainstream but very clean and melodic with, like, flutes and xylophones. I like colours. And I said to myself, "You need to be true to yourself here." Blackest would've released that initial version of the record but I couldn't imagine then having to continue with this sound and perform it live.

So can we expect brighter moods from you in the future?

I hope so. I'm more interested in making light and shade coexist rather than indulging in the darkness. I'd done that for many years. A lot of people do it and it's a bit of a stale concept at this point. Of course it can be done well and it's not my business to comment on the work of others, but so-called darkness can be a crutch.

"Bruell" is a good example of combining light and dark.

That was one of the last tracks I made for the album. I was watching a documentary about dub, and most of the early stuff was made on only four tracks. I wanted to try working within the same limitations. So I sent the MS2000 into the looper and then to this Tascam 244 multitrack recorder. It's from 1978 and sounds fantastic, it's not lo-fi at all.

I wasn't authentically using four tracks because I would bounce multiple takes onto a single channel. But the idea was to see how I could arrange these four tracks using one sound from one synth. Then I produced it in the computer and added a little extra bass and percussion. I EQ'd and saturated certain tracks on the Tascam, which gives each sound a distinct character. The structure is quite simple but I had a lot of fun editing and overdubbing and contrasting very gritty analogue sounds with extremely clean tones.

What other machines contributed to the colour of the record?

The Omnichord OM-250m helped a lot. You can play very precise chord progressions and solo over the top with this metal touch plate. A lot of the sounds are pretty comical but some of them are very delicate and pretty. The metal touch plate can also create strumming effects, as if you were playing a harp or a guitar. The MS2000 also has a vocoder, which I used to make chords out of my voice. You can hear it in "Target."

The second half of the record has these bass sounds that blend into the reverb, which gives the impression that the bass is very wide and creates an almost vibrating, wobbling movement. What's the story there?

Again, it's the MS2000, but I also use the ARP for basses. I make most of the kick drums with these synths, too. Once it's in the computer, I'll layer cleaner subs with subtle synth sounds and push them together with a compressor. Sometimes I end up with layers and layers, all with different types of EQ and compression and different amounts of automated spatial effects.

Earlier you were talking about retaining dynamics in your music. Do you bother with things like parallel compression?

I like parallel compression. I don't use limiters. I've found that a lot of people in dance music use limiters as a creative effect but I've never tried. When we talk about loudness, you tend to think of compressors and limiters but I think EQ might be even more important. This is basic stuff but often enhancing one sound requires you to remove frequencies from other elements in a track.

Space is also important, especially moving sounds between the foreground and background. So for instance, I might have different bass elements where one sits at the front of the mix while another rests in the back. It creates a sense of perspective that's very important to the mix.

Silvia Kastel plays this year's Sónar Reykjavik, which takes place between March 16th and March 18th.