It's 11am on a sleepy Saturday in Hammersmith, in west London. Outside the Lyric theatre a group of hipsters have congregated to smoke cigarettes. Up on the first-floor garden balcony men and women are bending themselves into a variety of yogic contortions, and the theatre bar is full of people eating granola. A rock concert appears to be going on in Rehearsal Room 2, where I'm supposed to be sitting in on a run-through of A Midsummer Night's Dream. The studio's doors are locked, and I'm pretty sure whoever is inside won't be able to hear me knocking. Has rehearsal been cancelled? Not according to the box-office staff, who direct me to the hipsters, still smoking unhurriedly, outside the front door. They turn out to be half the cast of the play, and they are obviously running as late as I am.

Among them is Ferdy Roberts, actor, musician and founding member of Filter Theatre, whose version of this Shakespeare comedy visits the Bord Gáis Energy Theatre next week, as part of Dublin Theatre Festival. Tall and bearish, with long hair and a gnarly beard, he looks more like a member of an electronic band than a classical actor. He rolls another cigarette and begins to talk about the rough-and-ready, rock'n'roll reality of Filter Theatre's latest production, which reinvents Shakespeare's play with a blend of live music and comedy improvisation that presents the text and spirit of the play in a style that is fresh but faithful.

The production originated at the supercool Latitude Music Festival, in 2011, where the company came together for a week to “have a crack” at the comedy, despite the fact that Roberts and his collaborators weren’t particularly inspired by the idea when it was suggested to them by Sean Holmes, who became one of the production’s directors.

"To be honest, at the start, we all went 'Oooh. Really? Another Midsummer Night's Dream?' We had all seen it so many times and just thought, Nah, not interested. But then we thought, Well, maybe that's the reason to do it. Everybody knows it. How can we make it different?"

Casting stereotypes

When they had their first production meeting, Roberts says, “it all started to come together. We work a lot with the same actors and musicians, and when we were talking about casting, who would play Oberon, king of the fairies, everyone said, ‘Well, you, obviously. You are tall and hairy with a deep voice.’ But I was, like, ugh, I don’t want to play Oberon. And one of the other actors, Jonathan Broadbent, who is small and slight, was talking about how he had played Puck, like, 12 times, and we thought, Why don’t we let him play Oberon? And so all of a sudden we had this sort of reversal of the typical casting stereotypes, and that became our beginning.”

In its first incarnation, in a tent in front of revelling festivalgoers, Filter performed their new version with just a drum kit and musicians. The success inspired a similarly “thrown together” national tour in 2012, but when Holmes, who is now artistic director of the Lyric Hammersmith, invited them to perform it in a traditional venue “we decided to make it more of a visual experience. We wanted to design a set that would still keep hold of the improvised nature of the production and the liveness of the music, and would also give us a space in which we could play.”

The set, a large white room made of paper, was also designed to “give a nod and a wink to all the productions that have gone before, the ones that people remember, [such as] Peter Brook’s white box – not because we want people to think we are trying to break boundaries but to make sure what people are experiencing is a fresh and live event.”

Roberts is also keen to stress the collaborative nature of Filter’s work. “We are a devising company, really, and when we started out we wanted to make our own new work. We didn’t want to stage classical plays.”

Music was at the heart of their agenda. As Roberts explains, “the company grew from the three of us – me, Ollie Timsdale and Tim Phillips – studying in the Guildhall together, where the drama and music department were in the same building but weren’t connected at all. We were all socialising together, sharing influences, but not being able to apply them to our work, and we thought that was a bit of shame.”

Music as a tool

The company was born after they graduated, and the idea of live music as a tool for the creation of new work became “their calling card”. It was only when Filter was invited by the National Theatre in London to “see if we could apply our style, our mode of working, to a classical play that we got interested in traditional texts”.

At the core of that theatrical approach is the idea that “everyone is in the room from the very start and for the whole of the rehearsal period; that sound, design, music is as important as the actor; that everyone in the room has an equal voice.”

Although the company credits a director for most of its work – in this case Holmes is credited alongside Stef O’Driscoll – Roberts says that the director “is just another skill in the room. It’s not just a person sitting at end of table, shouting out ideas. Their job is not to come up with the style but to respond to what we give them, to try to solve problems and knit the material together. That is one of the reasons we set up Filter. We thought, Why spend all this time training just to be a mouthpiece for someone else?”

O’Driscoll describes the process in a similarly open-minded vein. “For most of rehearsal it’s like everyone in the room is director. You are just another generator of ideas. But when we get into tech and production, when everyone is busy being on stage, you have to be more active, feeding in useful ideas and pointers about what you can see with an outsider’s eye.”

The rock concert is still going on in the rehearsal room when we enter, the cast playing a theatrical version of dodgeball to the heavy soundtrack as a warm-up exercise. Blood is certainly high, and with keyboards, electric guitars and drums at the ready the actors are primed for an anarchic 90-minute romp through the forest of Fairyland. This is day four of a five-day rehearsal, then it’s off to Brisbane, followed by Dublin, to make the show new again. This is rock’n’roll, indeed.

A Midsummer Night's Dream is at the Bord Gáis Energy Theatre from Wednesday until next Saturday, as part of Dublin Theatre Festival; dublintheatrefestival.com