As fluid and natural as the coming together of Adam Wiltzie (half of heavenly drone legends, Stars Of The Lids) and pianist Dustin O'Halloran (also film composer and co-founder of Devics) was for their first album as A Winged Victory For The Sullen back in 2011, the decision for Wayne McGregor to have them score his latest dance piece, Atomos earlier this year was perhaps even more organic. On their self-titled debut, O'Halloran's lilting gift for piano melodies (which have graced some dozen movie scores, including Sofia Coppola's Marie Antoinette, and Drake Doremus' Like Crazy) became slowed to fit Wiltzie's gradual drones, leaving a perfect canvas for lush string and horn arrangements to flourish.

While Wayne McGregor and his dance company, Random Dance, has been dealing with abstract expressionism in movement for years now, developing a unique movement aesthetic that eschews traditional concepts of meaning, and challenges the bodies of his dancers to the very tip of human possibility. He's perhaps become best known for choreographing Radiohead's 'Lotus Flower' video and Atoms for Peace's 'Ingenue', while his previous musical collaborators have also included Ben Frost for 'Far', Jon Hopkins for 'Entity', Olafur Arnalds for 'Dyad 1909', Max Richter for 'Infra' – so a McGregor score has become something of a rite of passage for the new international wave of instrumental composers. Anybody who's aware of the colossally slow tones of Wiltzie's previous project, Stars of the Lid, will perhaps understand that – despite their incorporation of soaring melodies and comfortably western classical instrumentation (alongside synthesizer and guitar drones) – A Winged Victory For The Sullen simply don't move at a pace one would normally reserve for dance. But then again, McGregor's company don't really 'dance' at all in the traditional sense.

The resulting score for Atomos is a mountainous achievement that deserves to rank alongside the high points in both Wiltzie's and O'Halloran's back catalogue. 11 untitled pieces (although twelve are numbered – the fate of number four is apparently not to be discussed under any circumstance) flow gently through reimagined motifs that re-emerge here and there, mutating melancholy synthetic drones into towering placid string arrangements, and consistently returning to the sheer power of O'Halloran's restrained piano chords. The entire album plays out as a single 63-minute epic, and besides O'Halloran's simply stunning piano strokes, the pair has grown leaps and bounds beyond the relatively populist classical drone of their self-titled debut. The string arrangements in particular are spectacular, weaving countless ostinatos into choppy seas of melody, occasionally parting (as on Atomos, part II) for a cello, viola or violin to arise alone momentarily. Besides the encircling string ostinatos that dominate the piece, semblances of rhythm also abound via uncharacteristic pulsating synth arpeggios. Wayne McGregor's instructions didn't come in form of rhythms or moods – as one would normally expect for a dance score. He rather instructed the pair via visual imagery. The piece is supposedly themed around the formation of atoms, and internally riddled with imagery of space and the cosmos, though the audience are confronted most immediately by a troupe of some ten dancers seemingly floating in all directions on the stage, lifting each other effortlessly into strange shapes, contorting their own bodies into hitherto unseen forms, and wordlessly evoking the seemingly random, and yet ruthlessly logical meticulousness of atomic nature.

I spoke to Adam Wiltzie and Dustin O'Halloran at their homes in Brussels and Berlin respectively via Skype, to discuss the making of Atomos.

Had either of you composed music for theatre or dance before?

Dustin O'Halloran: No, this was the first time for both of us working in dance.

Were either of you aware of Wayne McGregor's work then?

Adam Wiltzie: I'd never heard of him! But I was a little embarrassed, as he's quite a figurehead in the world of dance. It just goes to show, there's so many people making art in the world, it's hard to keep up.

DO: I'd heard of him because our friend, Ben Frost did his last piece, and so I'd checked out some stuff online, but I'd never seen anything live.

What about working to a stimulus this time round? I know you've done that before, Dustin

DO: Well yeah, it was our first time working with dance, but I think the music and dance - as a process - is a much more natural process than music and film for example. Wayne is an incredible collaborator. He gave us so much freedom, and basically the seventy-minute score we gave him is unchanged. We were able to use space a lot more, and we knew we had a lot of space to work with, and for us it's really important. Space is equally as important to the music as the music itself is, so we really needed it to achieve what we wanted.  So in that way, it's sort of the best visual collaboration that you can ask for – and also Wayne just gave us so much trust. I doubt other collaborators would give that much trust! So I feel like we were really able to put so much of ourselves into what we do. [Wayne] gave us some inspirations - a folder full of photographs and there was a film that he was inspired by – sort of like beginning points, and he would sort of interject inspirational ideas. But he never got into the nuts and bolts of our music, he never tried to tell us, "oh I think you guys should take this section and…", etc. He would say things like, "what if you went into a black hole and came out the other side?" We would have to take that and translate it into music – which was a really natural way to work.

Was it the music or the dance that developed first? Or did they develop independently and then get brought together?

AW: Over the four months of the whole process, I'd say for the first two months he gave us carte blanche to just create. He gave us images, photos, some small films, some words of inspiration - and after that was when we gave him a big block of music. Then we had a little more push and pull with Wayne, but he still gave us an incredible amount of freedom. Although we'd both never worked in dance before – so I don't really know what's the norm.

DO: When you work with Wayne, you certainly get micro-managed a lot less than when you work on a film.

I saw the Random Dance performing Atomos live earlier this year with pre-recorded music rather than the usual live performance, at Latitude Festival here in the UK. It's all very expressionistic and abstract, and seems not to be such a strictly choreographed piece

AW: Well if he does micromanage anything, it's the movement. There was one chance we had to see how he worked during the process, and we went to London to watch him work with the dancers, and as much freedom as he gave us, it's incredible to see the infinite detail that goes into their movement – because he was a dancer himself I guess.

DO: He uses the music as a sort of frame, a bubble for the music to stand inside, but everything that you see is so choreographed; every single moment. We got to watch them do this over the course of many shows, and it was amazing how detailed it is. He's choreographed every movement in that whole piece. It's incredible!

Where did all of the semblances of rhythm present throughout Atomos come from?

AW: I think it was maybe because we hadn't done [dance] before, but we were under the impression that there was going to have to be something rhythmic on it. But actually we ended up finding out that we were the only ones that thought that. We just figured that they were dancing, they need some arpeggiation or something to count to, but about halfway through [Wayne] said, "you know, you don't really need any rhythm at all".

DO: There was also this sense that over seventy minutes there does have to be this sense of variation. Unlike our first album, which was a listening experience, this was for a live performance.

AW: He did say though that he could have composed something to that first record. I guess we just didn't take him literally, but he was really serious.

DO: There was this one track we did, where Adam had this guitar sound that was sort of based on a tremolo effect, and it was nice because we were experimenting with a few ideas that had a pulse to them, creating it with [Adam's] guitar, or creating a little more movement in the strings.  I think the idea was to create variation, to create moments that were more active and moments that had more space so that people could really feel the journey. The attention span of a crowd is about twenty minutes, so seventy minutes is pretty long to ask - especially with contemporary dance! So the idea was to try and keep something that was engaging the whole time.

It's a broad question, but how do you compose? At this pace it seems difficult to improvise, or has improvisation played a significant role?

AW: Yeah, we don't really 'improvise' – we just sit down, and hash it out. We came up with some themes this time, so there was some variations on themes involved.

DO: Sometimes the process will start with the idea of creating a sound. Adam and I were taking a piano and running it through a lot of effects – back out, back in again, putting it in to the tape machine – doing like three or four different processes until we ended up with the sound we wanted. Then that sort of became a building block to a couple of the pieces. We created a texture that we came back to in a few of the pieces. It wasn't really a motif, just sort of a sound.

So let's talk a bit about how you both got into music, because your beginnings were both pretty different

AW: Well when I was a kid, I wanted to be a professional tennis player. But it didn't really work out, and when I was 15 it all fell apart. I'd always liked music and I went to university, and then it just happened really accidentally really. I had friends who were in bands, and I learned how to run sound, so I started touring around with friends of mine's bands, and doing music on the side. Years later here I am. I guess I'm a musician! Although I don't really know what I am – even now when people ask me I don't feel comfortable calling myself a musician, but I guess that's what I am!

What happened with the tennis?

AW: I just wasn't good enough. I was a nationally ranked player in the US when I was fourteen – so I had a lot of potential. My godfather won Wimbledon in 1963, so I have a lot of tennis in my family. But the fine line between being good and being talented and being someone like Nadal or Federer – it's so so difficult to get to that level. I just wasn't good enough. It's a little bit of a regret because I love the sport so much.

Do you still play?

AW: Yeah. I still follow it. I still play.

So with music, you started with a guitar I presume?

AW: Yeah 'cuz it was just something you could just figure out yourself.

Recently I was going back and listening to Starts Of The Lid's Music for Nitrous Oxide again, and it's so different from the other Stars Of The Lid albums

AW: It's horrible! I don't know what to think about that one… they're all time capsules in your life. But, jeez, that one did not age well in my opinion. But if it wasn't for that I wouldn't be where I am today. Putting out that record is what got me on Kranky – so I guess it's all strange stepping stones – but man, it's just seems like another lifetime!

Well something else that jumped out from me about that record was the extensive use of samples, from film especially. They cropped up here and there across the Stars Of The Lid's catalogue, and then on Atomos there's a track with some weird cut up vocal samples

AW: Well actually, I don't think we're going to tell you what it's from, but a lot of that has partly to do with Wayne and some of the inspirations that he initially gave us, and this particular woman that he was quite infatuated with. Her name kept coming up as a reference or inspiration, so he said can you find some way to get her in there. Maybe he was talking a bit more metaphorically, but Dustin came up with this amazing way to get her in there.

I remember listening to Stars Of The Lid's 'Requiem For Dying Mothers, Pt. 2' when I was much younger, and there's a part in the second half of that song, where out of the ambience arises this string section. That seemed like a big moment for me then, as at that point, I'd never heard those two things together at the same time. How did that blend of organic and synthetic first end up happening?

AW: I'd been messing around with strings since the very beginning, but it wasn't until like '97 that I started using them a little more prominently. For a long time I had no idea how to notate … every time you create something it's this little stepping-stone, and you get a little better at it, and you get a little better at it. So I think I'd just reached this point where I knew how to mix them. That was actually at a point where I was playing cello and learning how to layer cello, and make it all fit and be in tune with everything. That recording ['Requiem For Dying Mothers, Pt. 2] I recorded in 1999. I mean I'd like to think that I was recreating the wheel, you know, but I think I got lucky and it just happened to be an early moment in time before a lot of people were doing it. If that song came out now, it would be a little more commonplace. I think I just got lucky, man.

So with musical notation, did you just pick it up then like you described? You knew nothing of it before?

AW: Well even now I still don't feel like I know what I'm doing! I have a little bit of a better understanding of how elements interrelate. It's just like learning another language really. For both Dustin and I, coming from this monolingual society, we both picked up another language after moving to Europe, and for me it was learning another language that really helped me sort of grasp the concept of score notation. It made me lose my fear of it a little bit. Whereas I had thought we could never learn this – neither of us were classically trained. Once you get over the hump though, and can learn a second language, they all kind of become easier, and that's the way I feel about notation.

DO: And luckily, we've also had incredibly patient string players. Neil, Margaret and Charlotte are our core trio, and they've been so patient, and also helped us understand how we want to translate things, and taught us. It's been a really great relationship, 'cause we've been able to really learn a lot, and get to a place where we have a bit of confidence about it. We'll sit down and discuss the possibilities in how to notate, and what's really possible in the instrument. Neither Adam nor I were schooled in this, so it's pretty valuable. I think whether you go to school or not, you still need real time experience, and so I feel like we missed a lot of steps in a way, before getting to work with some amazing string players.

Dustin, you career began with a much more traditionally-accepted style of song writing, before suddenly embarking upon this far more academic musical route with those records of complex solo piano pieces. How did this transition happen?

DO: Well when I first started playing music, piano was my first instrument – and my first love I suppose, in music, was playing classic – but with only a few simple lessons. And then I didn't play for twelve years, and when I started the band with Sara Lov, when I started Devics, we were writing songs, but in the background I was sort of always working on the piano. It was just something that was bubbling for a long time. I was always doing it on my own, and when I moved to Italy, my wife Francesca had a piano, and I just fell in love with this piano, and literally just started sitting down and working on these pieces day and night. That sort of just sprouted this whole new part of my life. But I think it was something that was always inside of me, it was just a matter of time that it just kind of developed. It's like sitting on a cliff and looking down: it's a huge world and there's so many possibilities.

In the development of your piano playing, I find it interesting how sparse and conservative your playing with A Winged Victory is in comparison to your faster-paced, note-heavy piano solos pieces.

DO: Well that's where Adam and I come together. I'll bring Adam a piece, and he'll say, "I love that piece, but just do it at half the speed!"

It must take a lot of restraint?

DO: The first thing Adam and I worked together on was my album, Lumiere, and I had this piece that I wanted him to play on. I had already recorded the piano part, and when he recorded on it, I realised that there wasn't enough space for his part, and that there just wasn't enough room.

AW: Whiskey always helps.

DO: [Laughs] Yeah, it helps slow things down.

Swap the wine for whiskey and the piano gets slower an slower, eh! So other than the usual, often-cited list of languid musical influences over the project – Gorecki, Briars, etc. – what other artists made an impact on you, something we might not expect?

DO: Fleetwood Mac?

AW: Well, there's a couple of more obscure records, like The Caretaker [Jim Kirby], or Maryam Guebrou on Ethiopiques, Volume 21. But these are just things that we started listening to together when we were first making music together. I still listen to music, but not like I used to. I know that they're there – things that you're influenced by. There's everything that happens, for everyday your whole life: a certain wine you're drinking, you know, mustard, every thing you're doing your whole life is a sort of collection of inspirations. You in the music press put everything down as if it's only music that's inspiring, but for me and definitely for Dustin, visual art is a huge part of it, Rothko painting, and, man there's so many things. And I didn't realise it until much later. Moving to Europe and this just visual aspect of the city I live in, how much of an influence that has over my writing. When I was younger I just didn't realise. I was just like, into Eno and drone music – but there was so much more to it than that.

DO: Well like we said, for Atomos, Wayne sent us these photographs and films for inspiration. Atomos is actually based on the formation of atoms, and outer space, and in a way, those things had more of an influence than other music. Those had an impact on the way we were thinking about the music. And [Wayne] would use really visual references when he was describing certain ideas for his piece. I think both Adam and I have always thought of things like that. When we were making our first album a lot of our song ideas came out of conversations about human existence. We would get into these philosophical conversations, and when you start getting into that like, cosmic realm, that literally has a huge influence on what you play.

AW: And also just spending a bunch of time together in Italy and eating a meal together. This wine and cheese that we'd eat, and then suddenly, we'd go back into the studio and it's all coming out of you.

How does this music affect you? There's something about this music which feels difficult to own somehow; difficult to believe that it didn't just come into existence on a CD

DO: Sometimes the process of how we develop things goes through so many layers, that sometimes I can't even backtrack to where it started. Sometimes I feel the same way, and I don't know how we got there.

AW: Absolutely. Once you get to point B I have a really hard time remember where point A was.

DO: And I think our ability to know when to drop ourselves out of it, and let the music exist outside of our own egos is part of what makes it work, and what creates that feeling.

So you're both musicians that got going in the late-90s when everybody was still buying albums, and you've worked and worked and now come out the other side when nobody's buying anything any more. What do you think about the entire world of music as it is today in this sense?

AW: I feel detached from it. I know if you read any sort of commentary that there's a general impression of a generation of freeloaders that are starving the artists' creativity, but if anything for me, I feel lucky for where I am, and I don't think it's starved me creatively. Maybe I'd be making more money if people weren't just downloading everything for free – but there's only so much you can control.

DO: I think there were obviously more ways to make money in the past with people buying more records and all that – but why you make music hasn't. Either you're just compelled to do it, or you're not. It's always been hard, and music's always been remote – for me it doesn't feel like anything's changed. The struggles have changed, but music is still a labour of love.

A Winged Victory For The Sullen will be touring the UK later this month:

OCTOBER
Fri 17 - St George's Church, Brighton
Sat 18 - Dimswn, Cardiff
Sun 19 - Milton Court, Barbican, London - SOLD OUT
Mon 20 - Milton Court, Barbican, London

Atomos can be ordered via erasedtapes.com