A hooded figure burns an incense stick at the front of the stage. It is a ritual, light flickering across his face as the flame dies down and smoke billows out into the gathered mass. The man walks back to his allocated spot where he directly faces his accomplice, who is hidden in shadow barring the dots of light emanating from his various control panels. They begin their work, and deep thumps shake the room while synth lines race alongside. Vocals sound as though they have been sung into a portal in another dimension, and we are hearing only the garbled reverberation on the other side. An almighty horn sound emanates from the speakers, a powerful boom that sounds like an ancient rite used to stir the dead back to life. This is not a pedestrian run though of a band's latest songs – this is a journey into another realm.

Robedoor are the duo that have managed to transport us away from the grubby surrounds of Elephant & Castle. The Los Angeles band's name is apparently derived from the practice of smoking Robitussin-soaked Doritos through a bong, which is a pretty apt tag for the hallucinogenic music the duo produce. So prolific are the band that navigating their back catalogue can feel like steering a ship through a thick fog. A slew of records, CDRs and tapes on various bedroom and underground labels pivot between doom, drone, psych, tribal stomp and primal electronica. Listening to early releases you can almost feel the sweat dripping from the tiny suffocating rooms the band's music is echoing through. This gradually progressed to a fuller and more exploratory sound with the addition of drummer M Geddes Gengras, who joined the band for a few releases and tours. His departure forced the band to evolve once again, streamlining their sound into this year's excellent Primal Sphere album, which piles blaring keyboard upon driving drum loops, advancing their sound forward whilst retaining its urgency.

The Quietus sits cross-legged atop huge speakers, in the depths of Corsica Studios, with Robedoor's Britt and Alex. As we chat, aiming to give some shape to the band's murky form, trains rumble overhead. The subterranean environment feels a fitting place, as the artwork for some of their many releases conjures up images of journeys into the heart of our own planet. The combination of this 70s pulp sci-fi artwork and their hazy music lends the band a mysterious air - which is somewhat shattered by how open and friendly they are when we meet.

Outside of the band Britt Brown and his wife Amanda run L.A.'s consistently fascinating Not Not Fun record label, whilst Alex Brown is a cheesemonger - and excited for their visit to France, so he can try some cheeses which are illegal in the US. But there is something otherworldly happening when you experience Robedoor live, or listen to some of their rituals committed to tape. We're trying to ascertain just what that is.

Today feels like the beginnings of a bleak European winter, which your music really suits despite the fact that you guys come from L.A. Does it feel like the European audiences understand your music a little better?

Alex Brown: It's funny, that question comes up quite a lot - that we make this brooding dungeon music while living in happy la-la-land. But L.A.'s got a perverse weirdness and bleakness to it, and it is this sprawling urban world that influences our sound. I mean, how bleak would we be if we lived in Portland or something? 

Britt Brown: We would just be opiated way too much.

AB: Making dripping cavern sounds. 

BB: I think that there has been more of a European connection in the past - we would get weird obsessive emails from people in Italy and places like that, whereas in L.A. we always play at the end of the night to just the diehards. There's a history of goth in L.A., so there's plenty of people dressed in black being mopey, but they are all doing it pretty shakily, listening to darkwave and being cute about it. So there's never been other bands particularly that it makes sense to play with. I think for both of us the darkness in the music is offset by really liking where we live. But there is also a dark side.

AB: There is plenty of scum in L.A.

BB: In every place that has a glittering facade sketchy things happen. Not that we are necessarily always trying to tap into that, but it is a huge part of what I like about L.A.

To me your music sounds both primal and futuristic – perhaps the sound of a future where we have rid ourselves of the shackles of technology. Was there an idea to retain a certain rawness?

BB: Absolutely.

AB: Totally.

BB: I don't think we are capable of otherwise.

AB: Part of the primacy is just who we are as musicians, or non-musicians that make music.

BB: We kind of like music that flirts with anti-musicianship. I respect musicians that are incredibly deft and capable, but it's not typically our favourite music. I mean, we're not really capable of doing that polished kind of recording process anyway, but the version that ends up on the record is the one that when we listen back and are making our notes, we call 'savage version' or 'psychopath version'. It means we were really unhinged, or it was a take that would be hardest to redo - that is the thing you want to capture.

AB: The music is an immersion for both of us playing it. To draw a hackneyed comparison, it's like minimalist art, which is successful when it physically affects you, and our songs are most successful when it's like, 'I just listened to this, and if I am not stoned lying on the ground in the dark, I wish I was'. 

Is the process normally to jam until you have something that you like and then you will record it?

BB: It used to be that, very purely, but I think in the past couple of years we will start with an element that we have a little pre-meditated, a beat or a loop or something that I know we want to start with. I think in our mind a lot of the songs are very much songs - the intention is just to play them with a sort of primal chaos. They do not often sound like songs to other people, which I find fascinating and funny. It's why this band has always been so fun and enjoyable, because it's like trying to control something you have no hope at controlling.

I can usually hear song structures.

BB: Oh yeah, some of them I think very much so, but along the way there have been very loose ones.

AB: There's a boredom that I think naturally is going to happen if all you do is improvisation. We did that for a while, but there was no longevity in it. I mean, it's hard enough to keep making that interesting for yourself, and obviously if it's not interesting for you then what the fuck is it going to do for anybody else?

It is kind of the hardest bit – finding the interesting middle point between a structured song and improvising.

AB: And that grey area has a lot to do with the way that people approach the music they are making. Often the most uninteresting improv is done by people that have too much talent. It can sound really contrived and weirdly predictable and there's no magic or energy behind it.

BB: It's not the music I am ever drawn to listen to, and at times I wonder what the repeat value is for some of our own records, because they are so specific to us. But for some reason the ones that are the most structured are the ones that I am most fascinated by, which is the way we have been headed in the last four years of the band.

Yes, your sounds seems to have evolved from the claustrophobic early recordings to a more panoramic scope with Too Down To Die and now the more skeletal Primal Spheres. M Geddes Gengras left the band before this release – did that have something to do with the most recent shift?

BB: Along the way we have had various people play with us, and he came in and it fit really well, but the type of musician he is and his tastes led us in a more rock direction. It made sense at the time, but I think we both reached our limit and we wanted to get a little closer to the original vibe but played more deliberately. And also, it got too layered - too many overdubs and too many people's ideas, and I think sometimes we can vibe better a little more braindead...

AB: And it makes it a little more easy to perform, too. That is the other pitfall with improvisation - is this next show going to be amazing or mediocre? Anyone's fucking guess! When you have more control you can dial into things when you are expecting them to happen. There are still tons of variants in every set but it just makes it so much more fun.

So Primal Spheres was constructed in a more piece-by-piece way?

AB: Absolutely, and I think the big switch was that Britt was getting really into creating these drum beats, and those worked well as elemental structures for the songs. It keyed into both this idea of advancing the concept but also regressing it, so that we could be just as boneyard as some of the old releases but with more control over it.

'Stagnant Venom' sounds like a large ship sounding its horn – is there a voyage you are hoping to take the listener on with this record?

BB: The big picture narratives are a little formless to us sometimes. There have been albums where we have discussed them very specifically, but it is more that each song is the journey and then they are just put in an order that sort of makes sense. We have a little bit of a Frankenstein quality, because we are always recording so much and shelving so much that what each album ends up being is a little bit of an odd bag. But we definitely always want the fucking foghorn keyboard sound that Alex does! It is one of our touchstone blaring sounds.

AB: And that is the other key, to have good connective tissue between the stuff that we are doing now and the stuff that initially got people psyched about the music. We can find those touchstone deep throbs, grinding drones and thumping Satan drums, and all that can be moulded more intentionally. But some of those early noisy releases were like, 'Ok, this is about being stranded on the ice in Antarctica'.

BB: In the future.

AB: With some kind of sea beast chasing you.

The artwork that accompanies releases often has a 50s sci-fi feel. Do you try and pair a visual image to match the music?

BB: There are a number of barely-in-business grungy LA book shops stacked full of rotting 50s and 60s horror and sci-fi paperbacks which are a source of inspiration. Going through them and just looking at covers, one will immediately strike me as being the most Robedoor image or title which triggers an idea.

This is the first time you guys have toured Europe since 2006?

BB: We've toured the States between then, but yeah, we have just never been able to come to Europe. Part of it is the way we pursue the band, we just practice once a week, and it is always enjoyable but we are not hustling the band in a way that most people do. Most touring is dominated by popular acts – it is harder for more obscure people to tour because you can't break even. In the states we just get in my Subaru and drive around and play in living rooms and it doesn't cost that much, but coming here you need someone who wants you to come and will help logistically.

AB: When we were here in 2006 our music was very different - we were so dependent on amps as instruments. We had four Sunn amps all turned inward forming a weird Stonehenge with a tarp over it.

BB: You couldn't really see anything - it didn't really make any sense to be on the stage. It ruled to be inside of it and when we played on the ground at some scuzzy LA art gallery it would be awesome, but it probably didn't translate that well to a larger venue. But I think so much music is performed the traditional way - why not have a few freaks that are doing it some annoyingly weird way? So this is kind of a new tradition for us - having a table where we face each other and are totally exposed - but we are figuring out how to make it work.

So your live set-up is different now?

BB: We have had this set -up for about two years but haven't toured it - we have replaced the drummer with drum machines and the guitar with keyboard.

AB: It still sounds kind of similar, though. It is definitely the most technologically advanced we have ever been. There are a lot of buttons and switches, a lot of things to plug in.

A lot of things that could go wrong?

AB: More a lot of things to figure out exactly how and when they are supposed to happen. There is a certain safety net that we have in the kind of music that we make - worst case scenario it is blindingly loud and evil sounding, and the people that came for that are going to walk away happy.

BB: There are the nights when the sound system is great, and the monitor is good and we can hear each other, and Alex can bring things in and out with what I am doing in a really organic way. And there's the shows when it is pitch black and you can't tell what is making what sound. But I think it still works because a lot of the songs were designed to be a sort of inner energy or heartbeat.

Britt you run the Not Not Fun label - so why are Robedoor records on various other labels, rather than just putting them out yourself?

BB: I don't think our music fits in with Not Not Fun all that well. Once in a while it does and I am always happy to put out those records, which we have, but when other people ask us it is flattering. I love working with other labels, and a lot of the time it is someone we know or a friend, and I would rather…

Keep things separate?

BB: Yeah, apart from the times when we have had an album that we are ready to put out and no one else can do an LP. We put out Too Down To Die because I was stoked on it and wanted it to come out. That is the cool part about running a label, you can just do it.

AB: The first couple of years too there were all these weird bedroom labels who offered to put out a tape or a CDR.

BB: It was a very inclusive and extroverted community for a while. People would get in touch not even necessarily to compliment the band but to swap tapes - 'do a tape with my label' or 'do a split with my band'. Without even trying we ended up putting out all these CDRs, which we released just because there was just this community. I think everyone was just buying each other's releases - it was low profit and low expectations, but really rewarding.

Has that changed in the last few years?

BB: It is completely different now, it's much more tribal, and I think a lot of labels are aggressively curated. They will put out just one genre, strictly 70s drifting ambient new age music, which is okay, but it used to be this mixed bag. We used to play such weirder shows, where there would be all kinds of freaks on the bill - and then it hit a point where we'd be playing shows with six solo guys playing harsh noise. I am surprised that people like such a straightforward show - I like it when it's a grab bag of all kinds of weird shit, with good and bad stuff in every genre.

I know you said you put out some pretty raw recordings – when you record, do you keep in mind the format it is going to be released on?

BB: When we are working on an LP, those are our significant pieces that have been developing live and we really want perfect, so a lot of time goes into them. And every once in a while we will record something that was an awesome take and it will maybe strike us as an ideal tape track. I like the LPs to be things that we've refined a little more obsessively.

Lastly, Alex you have a food blog called 'Hot Knives' - do you write about food while you are on the road?

AB: I try to log the weirdness of eating and drinking on tour. It's not like going to restaurants and reviewing them, it is just finding interesting recipes or writing weird whimsical meditations on what a beer made me think about. I am not a very technologically advanced human, so I don't enjoy being plugged in all the time. But I am curious about the food that we are going to be served at different places, and hopefully I will be able to drink some arcane beers while I am out here. Other than that, I'm just trying to see the world.

Robedoor's Primal Sphere album is out now on Hands In The Dark. The duo play at Birmingham's Bring To Light festival this weekend - for more information and tickets, click here.