It was a strange crowd at the DRAF gallery. Set back from Camden High Street, the venue seemed a long way from the normal stomping ground of the people hanging around its front door, some dressed in Berlin black, others in art-dealer tweed. Up a flight of stairs, the venue opened into a main space, stark white and filling up. In the middle of the room there were three instruments: two series of long metal cylinders in various sizes, and an upright stringed instrument, running from floor to ceiling, on which heavy woven metal cords were brought taught against curved lengths of wood.

These instruments were built by Emptyset. Throughout their decade-long collaboration, Paul Purgas and James Ginzburg have explored the intersection of architecture and sound art, with projects and installations based in decommissioned buildings, nuclear power stations and gallery spaces including Tate Britain and Spike Island. The show at DRAF was the final act in a year-long interrogation of the building, beginning with architectural and acoustic surveys, and culminating in two performances. These were also Emptyset's first fully acoustic shows.

The performances hinged on the metal cylinders, which the pair hit with selections of mallets, picking out complementary rhythms. The strings, meanwhile, added a unique new timbre as they reverberated through the room. Towards the end of the performance, four vocalists appeared, singing wordless phrases that fell somewhere between voice-as-percussion and tone poem.

The show marked a departure for Emptyset. In the past, their work has been about pummelling volume and battering the audience into submission. Here, though, they were concerned with the power of quietness and the implications of real, human interaction with physical instruments, as they also explored on their most recent album, Borders. Gone were the complex patterns and the intricate signal chains, replaced by, well, two men hitting things.

The next day, in the basement of Somerset House, where Purgas has a visual art studio and where the duo have plans to build a recording space, we spoke about the performance, architecture and sound, and about new departures for this constantly innovating pair.

How did the DRAF commission come about?

Paul Purgas: They were interested in us doing a performance as part of an annual event they do for Frieze art fair in the gallery. Usually they invite a musical performer to contribute. They'd just opened the studio space as an extension of the gallery, and they were developing this idea of residencies, usually over the course of a month. So we decided that instead of performing as part of a Frieze event, it felt more appropriate for us to do something more considered, to take some time, to work and develop an idea over an extended period.

I think for us as well it was about trying to find an opportunity to step into another way of working. I think having worked specifically through electronic means for so long, and with Borders extending out to electronic and acoustic, it just felt like the right time to do something that was actually very present, and potentially exposing, but could also act as a meeting point for a lot of ideas that we'd been thinking about in the background, in the production of Borders: musical anthropology, the performance context, an idea of deep listening or a type of sonic attention, and then mapping that against some of the previous projects we'd done with Tate Britain or the Architecture Foundation.

Those ideas of musical anthropology were clearly much more present in Borders. How has that theme developed over the course of your work in the last few years?

James Ginzburg: It's probably been an evocation of something very primal, or primordial. Elemental, perhaps. I think a lot of these themes were submerged. The way we constructed our work previously was by circulating ideas and then distilling anything that was concrete out of them. We'd end up with an essence that would hopefully communicate itself without having to be explicitly stated. I think part of that was because we were looking at a universe appearing without human intervention. We were interested in ideas of the ways that complexity can arise out of voidness. I guess as we plotted that out and iterated it, it became more and more a world we were involved with and interacting with.

Before, we were sitting in a room together constructing pieces and setting up processes, or we were working on location in situations that were kind of like the ideal performative situations, but it was just us. We wanted to bring those two streams together, and doing that through the tools of performance seemed to be the most logical way of approaching this.

You start asking yourself questions like, "What does it mean to perform? What does it mean to be interacting as two people amongst a performance? What is the essence of an event in which sound is generated and people's attention is engaged?" I think that directed our explorations towards the fundaments of these kinds of experiences.

They're borne out of a sense of dissonance with the sort of performative environments we found ourselves in, where we were sort of extrapolating our process and bringing it into a festival or a club. That inevitably leads to looking at the history of music, and particularly the history of ritual music. It was interesting for us not to somehow strip the religious out of something, and provide a secular alternative, but to maybe arrive at a kind of third possibility, outside of that kind of dichotomy of secular and non-secular approaches to making music.

Do you feel like there's something intrinsically ritualistic about an acoustic performance?

James Ginzburg: We did a gig a few months ago, and I left the situation after a really long soundcheck thinking it would be really interesting to do something that wasn't so much about overwhelming the audience, and was more about drawing attention inward. I think a lot of our practice in the past has really come with this idea of very overwhelming, visceral experiences of sound, and how that affects your mind and body. But this is an inversion of that, this unamplified situation where you feel like your own attention is focused into what's happening. That creates a very different space.

Paul Purgas: I definitely felt that yesterday, this sense that there's an understated clarity to working in an unamplified way. And even after having performed together for years, finding yourself back in a position where you kind of lose yourself in a musical experience. This was one of the drivers when we were thinking about Borders—how can we, as musicians, ride back to that quite innocent experience of music where you just lose yourself into it. It feels like we're starting to arrive at that place, actually—developing a performance mode where you can absolutely lose yourself, and it can take its own shape relative to that.

James Ginzburg: I feel like ironically, a lot of what we were talking about with Borders actually felt like a more complete realisation of that attempt at innocence, because it felt like a non-hierarchical, inviting situation in which every gesture and movement of performance was directly translated into the environment and the experience. I guess it's probably funny us saying this, because it's a very obvious experience for musicians who have come at music publicly, using more traditional instrumentation. But for us it's a kind of revelation.

Paul Purgas: We were thinking about taking away as much apparatus as possible, and arriving at this sense of an inversion of that way of working previously. Within the framework of DRAF, it took quite a lot to enter into that situation and get the space acoustically tested and treated. There was a three-week install to get it set up to that spec, where we could do that and make it work.

James Ginzburg: On one hand, there's something very rudimentary about it, and on the other hand all the technology is kind of dissolved into the situation. So by the time the performance happens, it's rendered invisible and has this kind of elemental quality to it. But it is still very much borne out of a relationship between technology and sounds and space. Everything was based on the acoustic testing we did in the space, so there's a lot of consideration that ends up having technological vertebrae.

Do you think this marks a new phase in your practice, where you're no longer focusing on signal path, or manipulating signals with technology? Is this an inversion of that process?

James Ginzburg: We've become very interested in the idea of voice as instrument. We want to play with how that most direct human experience of music-making or sound-making can relate to what we're doing. It's both the continuation and a departure, and it's exciting to us that there's still actually a lot to explore, a lot to be fascinated by.

Paul Purgas: Also a practice doesn't necessarily have to be linear in its direction. We've obviously completed a large body of work over the last ten years, and there's been a lot of projects that have arrived in order to take us to this point where we can have the confidence to be able to step in at this scale. But nothing is ever completely dissolved—we might return to something that was an avenue that we never thought about at an earlier stage. It's nice to keep all the doors open.

It feels as if Emptyset has been based around quite a rigid theoretical framework, but within that you've moved off into all these different directions. Is it fair to say that Emptyset is often based around theory and process?

James Ginzburg: Process is a neutral tool in a sense. The application of process is more interesting.

Paul Purgas: An artist recently asked me, "What's the premise of Emptyset?" This is an artist who works within collage. When he looked at Emptyset, that's what he saw: a composite of various strategies of architecture, design, history, music, materialist theory. It's a form of collage we've formulated internally, within ten years of internal conversations. That's created a kind of foundation by which we know the rule set. Process is employed within that, as a means, but to us it never feels like it's the actual output. It's a tool that's required to give voice to space, material, form, structure.

James Ginzburg: What's interesting isn't rule sets or the questions of rigidity—what's interesting is the fluidity of the structure. What ends up being fascinating is the relationship between structure and process and fluidity. You employ all these strategies to work with that or to evoke things, to understand something, to relate to something.

Thinking about the interaction between sound and space, when you're working in a new environment, whether it's a nuclear power station or DRAF, how does it begin?

James Ginzburg: I probably have a different relationship to it than Paul does. For me, there's a sense of entering into a space and interrogating what it is, both in terms of its historical and architectural situation and also in terms of: what does it evoke? What experience does it communicate? Then there's obviously technical dimensions to responding to a space, doing testing in the room, thinking about how you can employ the space in order to create some kind of experience or setup or performance within it. That becomes another process, a certain set of possibilities and limitations that you work within to best communicate or evoke or express the experience of the place and the idea of the work.

Paul Purgas: It's about approaching an architectural process as a diagram or a technical formality, in which there are restrictions and parameters for what you can do, but also thinking about architecture as more anthropological, so all of the implicit histories that have been embedded and codified within it.

As you dig up those histories, do you feel like there's a social-historical element to what you do?

Paul Purgas: The idea of time is definitely something that was always central to how we were approaching it. With the project for Tate, there was a sense that this was a building that was in a state of dismantling, in what was a 100-year arc of decommissioning. So in the building, in the moment that we entered into it, certain components had been removed. The top levels of the space were being prepared for removal, and there was a sense that over the course of another 80 years or so, it would be returned back to the landscape. So it was very much about capturing those moments of architectural history.

To what extent is designing acoustic instruments similar to designing a signal chain?

James Ginzburg: I guess what's similar is responding to the unpredictable. Much with the steel pipes we were using at DRAF, you can make a lot of predictions and calculations, but when it comes to actually how material responds... We went through ten different mallets for striking the pipes, and each one has a very different quality, a very different envelope, a different sense of transience. So you're taking educated guesses, and creating some kind of tool, then the compositional process is seeing what the potentials and limitations of those tools are, and working within them. I don't think we ever expect to design something and it appear exactly as we'd imagine it would function or sound.

Paul Purgas: To reflect on Borders, that was a moment where we were thinking of building a hardware setup around a more transportable system for touring, so we looked at rescaling everything. Within that there was refining a signal chain by working with different units, being able to pop them in and pop them out, until you could optimise something and work in a modular way. When you're working with something that's entirely material, there are budgetary restrictions, especially when you're working at a more architectural scale. You can speak to an acoustic engineer or a materials expert, and they can approximate to you what something may or may not be or behave like, but in the end you just have to choose your parts, put them in situ, and then that is your framework for working.

So the compositional process is borne out of the materials?

James Ginzburg: Once you come into contact with those objects, there's a period of play, and then you create some kind of form out of those possibilities. We're always like, "We played with these materials and we came out with a 30-minute piece, but what were the other pieces hidden in that setup?" We tend to work very quickly, and discount certain ideas and focus on others. It's always a mystery what was there.

Paul Purgas: It's a bit like a techno game that I used to play with myself, like, if you give a Juno-60 to Juan Atkins or you give it Craig Leon, what are the totally different iterations that come out of that instrument? With Borders we had a very basic setup, and within a very short space of performing on it, even within the first couple of days, we'd arrived at some of the first tracks that were on the album. I think there's an interesting question about the way that things solidify out of a system quite rapidly. It's difficult to imagine what the other possibilities might be.

Have you been frustrated in the past by being pegged as a techno act?

Paul Purgas: Our backgrounds are so diverse. James was working in music that had a whole background in literature, and I was working as a contemporary art curator with a background in architecture but DJing techno since the '90s. You're a product of your environment and experiences. I arrived at architecture school through listening to techno and house music, learning about Chicago and learning about Detroit, learning about modernism, about urban planning. From there I entered into a formalised art education.

But music's an incredibly powerful means of entering into broader conversations around culture, civilisation, human values, society, living, architecture. There's such a broad spectrum that it can connect to without a lot of the baggage that other art forms have attached to them. I still really respect the fact that there's an immediacy encoded within the musical experience that visual art can't provide, because the means of critique are embedded within a weight of knowledge of art history, whereas in music, there's still an honesty. Also, thinking about the means of production within music, it's still amazingly—and more and more so—democratic. There's immediate access to it. You don't need massive infrastructure.

Thinking about that link between urbanism and music, how has the built environment changed, and how is that impacting on the music that's being made? Does the link still exist?

James Ginzburg: I think it's inevitable, and it's changing in parallel to the ways we interact. We're experiencing an enormous shift in the ways our built environments operate, the ways we exist within them, the possibilities we have within them, and the ways we exist within digital architectures. Both of those things are mirrors that we look into, and those mirrors change our sense of self and the ways we react to art and music.

This is the first time I've been in London in five years. I used to spend a lot of time here, and it's the most profound experience I've ever had of coming back to a place and it seeming like an entirely different environment and psychic space. I think it's really telling. It exposes changes that have been going on within my own life in the environments I've lived in, but I've experienced them incrementally, rather than the quantum leap that I've experienced here.

Paul Purgas: I remember from the '90s there was a really great Jeff Mills quote about how techno music was described as a virus in the city. It would arrive and build its own infrastructures. It was completely independent of any other current formal ways that music was experienced. It would set up in warehouses, set up record shops and labels, and build its own system. Obviously cities now have less and less possibility to achieve that. Thinking about the ruin of the last Mayoral stint here, that's completely dissolved a lot of the night-time culture. There's a sense that the future of music-making might not necessarily be equated to or about urbanism in any traditional 20th-century sense.

What do you think it might be equated to instead?

Paul Purgas: Not pastoral raving!

James Ginzburg: I guess it's a digital urbanism. I think you could say something about this very deep connection between built environment and musical experience, which I guess is perfectly expressed through the idea of the warehouse and the soundsystem. If you think about something like Boiler Room as an example, there's an idea that listening and environmental experience has been collapsed into a digitalised experience. It's less about a communal, built space that we're entering into, and more about a shared, digital experience.

I imagine, like it or not, that that's the inevitable evolution of urbanism. Cities become gated communities, and people get pushed further and further outside. It becomes more difficult to actually meet. That's the wonderful thing historically about the urban situation—it's a meeting point, or a point of intersection. But if that physical possibility isn't there, that point of intersection is going to be digital. In a sense we're very lucky to have had these experiences to interact with the physical spaces, with present audiences, both in terms of doing a commission like this at DRAF, or playing events like Unsound or CTM.

You could very obviously conduct a psychogeographical reading of London through music. Will that be possible if the geography in which music exists is entirely digital?

Paul Purgas: There'll be a type of media archaeology that will be translatable in some sense, but it won't be psychogeography in the way we understand it. It'll probably be more archival, let's say. A more systematised history, rather than a Situationist sense of discovering or navigating the space with its encoded histories.

James Ginzburg: Do you think that represents a dissociative process? Without the ability to interact or intersect in the physical realm, does that represent a dissociation from a concrete, shared reality, into a completely subjective experience? I try to imagine how you even identify period or time. In this archival model you've got a log, or things timestamped, but everything collapses here. You have aesthetics without any real spatial or temporal coordinates.

It's sometimes difficult to know whether or not there's an element of nostalgia. Maybe it's even conservative to want to try more traditional forms of making or listening to music. I hope it's not nostalgic, and I hope that there's something still relevant and that there are lots of possibilities still within that.

Paul Purgas: I think it folds back into that idea of being able to play a composite of different forms of experience. I don't think there's necessarily a sense that these are formal, traditional, conservative modes of presentation. I think it's more of a sense that there's a broader spectrum of presentation formats. There's more space for conversation to exist between the traditional and the non-traditional.