"What we're interested in, within the bounds of what we're looking at with Emptyset, is getting to the essence of the relationship between time, structure and sound," says James Ginzburg. Since they began working together around the middle of last decade, his work with Paul Purgas as Emptyset has touched on several interrelated disciplines - club music, noise, sound art, architecture - and has increasingly sought out the points of contact at which their shared traits bleed into one another. The result is a back catalogue that, played in chronological order, suggests the gradual eroding away of club-ready techno structures until only their fundamental particles are left in motion: from the four-to-the-floor techno constructions of their early releases, through the rippling fizz of second album Demiurge, to their newly released Raster-Noton debut EP Collapsed, whose great seething welts of static and distortion appear to cling only loosely to a centralised rhythmic chassis.

Emptyset was seeded in 2005 as a means of exploring the pair's shared interests in rhythmic music and bass. Both have backgrounds within Bristol's club music scene: Ginzburg runs Multiverse, the Bristol-based studio complex and collective of record labels that looks after (among others) Pinch's Tectonic and Subtext, the label run by Paul Jebanasam which has released much of Emptyset's recent music. He also produces sub-heavy, synth-led club tracks as Ginz, and can take joint responsibility for Joker's monstrous rave crushers 'Purple City' and 'Re-Up'. Purgas, who now lives in London (although Emptyset is nominally Bristol-based), has a history in art and sound art curation, a background in techno, and more recently has been curating exploratory electronic music events under the banner We Can Elude Control.

In keeping with their histories in club music, the early sound of Emptyset was a jagged and hollowed-out strain of minimal techno with a vicious emphasis on sub-bass, punchy enough to rattle the foundations of the Bristol basements from whence it came. "The physicality of the sonic experience is taken as given," says Ginzburg of the duo's music. "In a way, it's something that we wouldn't even have considered, because having come from and having been immersed in a culture that was very much oriented around overwhelming experiences of bass, to not have that within the experience of sound would be half an experience."

But working within a relatively straightforward club idiom had its limitations. "When we tried to move from doing a more traditional techno based project into an album format," says Ginzburg, "there was no way to do that that didn't feel cliched or like ground that other people hadn't explored previously and in a better or more coherent way." So by the time of 2009's self-titled debut album they had latched upon a way to incorporate randomness into their music-making process, by ceding control to a chain of analogue effects, processors and filters, through which they would send simple blueprint patterns of sine waves and noise. The final result, then, would be distorted, coloured and shaped by the properties of the hardware through which the original signal passed along the way. "The raw functionality of the machine gets imprinted," says Purgas. "For us it's almost been about finding certain pieces of equipment that have a certain signature to them, and then just running very basic sonic forms through them - a process of hardware imprinting."

"It seems like there are two possible approaches [to making electronic music]," says Ginzburg. "One is that you try and build from the zeroes and ones. The other is that you give the universe more credit than your own ability to make stuff up, and you say, 'Let's set up processes by which things will spontaneously happen, which will be more interesting than anything we could contrive'. Setting up elaborate processes and playing around with the thresholds within them gives an opportunity for things to happen from their own end, which we find more interesting than the idea of being the sorcerer."

Since their debut album, this set up has provided an increasingly effective means of reducing and distorting their music out of shape. 2011's unruly and violent second album Demiurge was haunted by the dancefloor, and its strobing rhythms and stinging lashes of distortion and sub-bass occasionally hinted towards the more regular structures of their earlier work. Released around the same time, single 'Altogether Lost' featured an eerily calm monologue by Underground Resistance's Cornelius Harris that hinted at the gradual crumbling of society's walls - appropriate, given the process of demolition the duo's music was undergoing at the time - and across a series of 12"s was tweaked for club play by the likes of Peverelist, Ben Klock and Chris Liebing. (It also landed in my column Hyperspecific's best tracks of last year). 

Both Purgas and Ginzburg discuss this ongoing process of breaking their music down in terms strongly weighted towards geometry and architecture. "If you see [the four-to-the-floor rhythm] as a square, almost, as soon as you think 'What happens if I push down on the top of the square and the sides start curving in, to the point where it literally snaps?', you suddenly realise there's this huge terrain of sounds and structures that we've maybe only started to play around with," enthuses Ginzburg. "It's exciting to discover that there's a door in your house that you hadn't noticed before, and there's a basement full of boxes that you could look in."

After finding a way to unlock that door, "the albums just developed in a particular order of complexity," says Purgas. "The first album was very much about working in the framework of a grid, then Demiurge came along and it was about how you could liquefy that off the grid - find a way to exploit rhythm and structure, but stepping off a traditional framework, and looking at more complex processes of feedback and new ways to create movement within that structure. Then after Demiurge we were, I think, trying to find a space where we could at least consider an approach for a third album."

They describe new EP Collapsed as a stepping-stone of sorts towards realising that new approach. Being approached by Berlin's Raster-Noton label to release music was "in a way, the perfect approach at the perfect time," says Purgas. "We saw it as an opportunity to present the process of moving between a very formal and structured approach to making rhythmic music, and perhaps a different way of looking at it," Ginzburg continues. 

The resulting four tracks are beguilingly contradictory. While Emptyset's most metallic, shockingly abrasive and violent work to date, they're also incredibly fluid, based around central motifs that continually change shape as through viewed from a slightly different angle each time they re-emerge. That was the intention, explains Ginzburg, who describes their thought process behind Collapsed as wanting to move beyond simple repetition of motifs and instead create something "in a dynamic process of change. I think the title track of the EP was approaching that moment where we managed to find a way of creating a rhythmical structure that, while it didn't repeat, you always had the sense of it being coherent." So 'Armature' screams and buckles like a steel and glass skyscraper imploding in graceful slo-mo, and 'Collapse' zooms in closer still and tracks the building's internal pressure as it builds up incrementally, before exploding in a shower of sparks and crystalline shards.

Live this new material is even more striking, and surprisingly fleet-footed despite its lumbering physical weight. At Unsound Festival earlier this month periods of apparent rhythmic fluidity and disarray would regularly resolve into more regular patterns, locking dancers into a groove for short periods of time before abruptly scattering them again. Despite speaking of their work increasingly in terms of vectors, lines, angles and geometry - something Purgas acknowledges when he says that "it certainly feels like we're less and less operating within the framework of making music ... we seem to have been talking more about and describing sculptural processes than we are talking about musical ones" - in the live arena especially, they still feel closer to composers of dance music, animators of human bodies, than pure sound artists. In that sense, their work asks similar questions as contemporaries and precursors like Pansonic and Alva Noto, and more obliquely the likes of snd, who run a related (albeit cleaner) line in mind and body confounding rhythmic interference. Collapsed consequently feels like an ideal fit for Raster-Noton, whose entire aesthetic hinges around bridging any apparent gap between gallery-based sound art and music. "[Those two worlds are] not necessarily in conflict," agrees Purgas, "but it's certainly about trying to differentiate between patterns and structures and musical forms, and the pure sculpting of sound, and what is that terrain that exists between."

The interests in structure, resonance and architecture that pepper conversation with Purgas and Ginzburg were fully integrated into the Medium EP, released at the beginning of this year. For its recording, they relocated to Woodchester Mansion, an unfinished Victorian Gothic building in the Cotswolds, and set up a soundsystem and microphone arrays throughout the house. As they pushed frequencies through the body of the house, the final recording captured an imprint of the building itself as it responded to the sound and shaped it. The mansion is a looming presence on the EP: sub-bass shudders through the walls and rumbles along dark corridors, and higher frequencies rattle staircases and ping-pong from surface to surface. Minimalist to the point of near-silence at times, it's a richly textured and subtle counterpart to the jarring assault of Collapsed, and a record that demands to be listened to closely and at high volume - either on headphones or speakers, the better to shake the foundations of your own environment.

"Medium was more about working in a skeletal form, taking very basic structures that we'd pre-prepared in the studio and then taking them out to a context that we couldn't really control," says Purgas. We've met to discuss Emptyset's music in the resonant surrounds of the Tate Britain and, appropriately, renovation work elsewhere in the building is sending great peals of atonal noise rippling through its central corridor. "We did not know how things would play out," he continues, "just setting up a sound system and microphone array and improvising with the feedback within that space, and allowing the architecture to impose its own dynamic set of circumstances onto what we'd pre-prepared. So for us that project was almost about - how do you take something out of the controlled environment of the studio, where there is an element of unpredictability but it's always contained within a set of constraints - [and] go into that environment with something that's a completely uncontrolled process."

Further delving into Medium, Purgas and Ginzburg have been commissioned by the Architecture Foundation - as part of their Sounding Space series - to turn the EP into a special site-specific installation in London. It will take place on December 13th in Amika P3, a former concrete construction hall previously used to test components of roads and the Channel Tunnel. "The production will be focused around the fact that when one amplifies the basic constituents of sound into a building such as sine waves and noise, what is reflected back contains an imprint of the space and all of its nuances," says Emptyset's text accompanying the installation, "just as when an acoustician plays pulses and sine wave sweeps into a space in order assess its properties, or when a bat uses echolocation to navigate through an environment." (More information and tickets - free with an RSVP - are available at the Architecture Foundation website.)

Speaking with the duo, you're left with the distinct sense that Emptyset offers Purgas and Ginzburg a flexible outlet to explore a wider range of interests that stretch far beyond the sonic. The inbuilt histories already present within spaces like Woodchester Mansion and the Amika P3 bunker add an extra dimension of living narrative to work that could otherwise either be seen as willfully austere or academic. In another crossing of disciplines, the duo have also recently been working on translating their music into the visual domain. AntiVJ member Joanie LeMercier's accompanying visuals for their live performances interpret it as a series of monochrome cracks, lines and end-points. They have also recently been working with Clayton Welham and Sam Williams to directly synchronise their audio with a visual output, the first results of which have been released as a video for 'Collapse', which you can watch above (for more information on the methods click here.) 

"With the Raster Noton video we're finding very very direct relationships between sound and visual outputs," says Purgas. "And I think our plan ultimately is to see how far we can take that relationship, and really consider all the narrative aspects of a project and how we can extrapolate from that, and equally reconsider - is Emptyset necessarily a sonic project? What is it fundamentally about, could it be about more than just sound?"

"When me and Paul started working together," Ginzburg agrees, "it was very much in the context of working with electronic music, but as we got to know each other we realised that maybe our primary interests were connected by music, but were very much outside the realms of music. Without realising it, Emptyset became an opportunity for me to move my creative processes from being strictly music more towards the things I was actually interested in. The weird thing about doing Emptyset is that all of a sudden we started thinking - and I started thinking - actually, could this be film? Could it be literature? Could we do those things?"