I'm standing in the Luminaire, one of London's nicer fleapit gig venues, as an American band called Yellow Swans takes to the stage. Two men from Portland, Oregon, dressed in standard indie-rock gear - trucker caps and checked shirts - stand facing each other on either side of a towering mass of wires and electronic gadgets. One has a guitar strapped to his chest while the other cradles a microphone. The chattering crowd falls silent as the speakers begin to emit a gentle hum, which rapidly builds into a distorted wall of feedback and electronic scree. It is a little like having a helicopter take off about three inches away from my face, but strangely compelling. There are snatches of recognisable sounds - the odd guitar chord; rasping croaks that could be vocals; some hints at rhythm, but few hooks for the uninitiated listener to hang on to. It presents you with a stark choice: take refuge at the bar until the band has finished, or immerse yourself in the abstract, largely improvised sounds and let them carry you where they will.
Yellow Swans are part of a growing global scene of "noise" artists who draw inspiration from the more extreme ends of various rock and electronic genres to create some of the most innovative and exhilarating new music around. Between this month and May, some of them will be touring the UK under the banner of "Free Noise", a collaborative live project in which a range of leading noise musicians, including Yellow Swans and the synthesizer duo Metalux, team up with free-jazz performers such as the British saxophonist Evan Parker.
As in free jazz, the avant-garde musical movement that developed in the 1950s and 1960s, practitioners of noise music are driven by a desire to push boundaries. Pete Swanson of Yellow Swans explains that "part of the excitement of playing improvised music is that it's uncharted territory; it's pure discovery. You're communicating with other musicians in a way that is almost accidental but is extremely invigorating."
Whereas jazz players do this with virtuoso displays of technique, noise musicians explore the limits of sound itself, using feedback and electronic man ipulation to coax unique, often ear-splittingly loud sounds out of their instruments. In one sense, this is nothing new; art ists and musicians have been ex ploring the properties of atonal music for generations. The futurist pain ter Luigi Russolo's 1913 manifesto The Art of Noises called for musical forms inspired by the harsh new sounds of the industrial age. Later, the French musique concrète movement drew on sounds from the "real world" for inspiration.
But while its ancestors belonged more in the refined settings of a gallery or concert hall, the noise subculture, which has existed in one form or another for the past few decades, is also a growing youth movement, with a unique tape-trading culture and a network of grass-roots concert promoters and record labels that spans Europe, the US and Japan. At the beginning of December, 6,000 people flocked to a Butlins holiday camp in Somerset to a weekend of noise, avant-garde and experimental music curated by the alternative rock group Sonic Youth. These are small numbers compared to such mega-festivals as Glastonbury or the Carling Weekend, perhaps, but when you consider that a large proportion of this crowd will have been in bands of their own, or that they put on shows or release other people's records, it gives you some sense of the noise scene's vibrancy.
Lee Etherington, founder of the Newcastle-based promoter and label No-Fi, which is curating the Free Noise tour, says the spread of noise music is in part due to new technology being more accessible. "Music has been democratised. People have now got software and samplers and it's a lot easier to make a piece of music than before. There's a lot of physical skill involved in playing a guitar, or a clarinet, or a piano, whereas you could almost argue that music has now been reduced to a kind of pure aesthetic skill."
Cincinnati-based C Spencer Yeh, who will be playing on the tour and is best known for his Burning Star Core noise project, agrees. Although he is an accomplished violinist who has collaborated with free-jazz musicians in the past, Yeh explains that part of the attraction of noise is that "people can pick up an instrument they're not trained on and, if they're serious about it, come up with some genuinely interesting stuff".
The noise scene is also fiercely independent, partly through necessity, but also in reaction to mainstream culture, says Yeh. "The DIY aspect can be very appealing to youth. Usually, young people are approached as just being an audience or a group of consumers and there's this kind of gate erected, which means they're not able to engage or interact with a lot of popular music. So they go and create their own."
Perhaps the only way left for musicians looking to escape from consumer culture is to search for a musical language that can't be co-opted, one that is constantly mutating. In this sense, noise music is a form of rebellion, but not along the tired old lines of sex, drugs and rock'n'roll. There is an even more fundamental attraction to the music, too: it is visceral and exciting. Music pervades our lives, but most of it is designed for people who aren't paying attention: the catchy pop chorus, piped-in Muzak at the supermarket, TV screens playing music videos at the gym. Noise music, which is rarely easy on the ears, challenges you to really listen.
The results can be uplifting, as Etherington explains. "I think in the past, noise music has had this reputation of being for misanthropes, but that's not really the case these days," he says. "There's a real joy to it, a real enthusiasm. It's all about taking pleasure in sonic extremes. A lot of noise shows are really cathartic - almost evangelical, sometimes."
The Free Noise tour runs from 29 April to 5 May at various venues. Info: http://www.no-fi.org.uk