Like T Na G, most people are for Sonic Youth in theory as long as they don't have to actually listen to them. They feel that it is a good thing that there are musicians dedicated to finding new ways of pushing the rock'n'roll boat out - so long as they do it somewhere due west of the Indian Ocean.

But while their mantlepiece may not exactly be creaking under the weight of platinum discs, Sonic Youth have established themselves as the American for avant garde and remain one of the most influential bands of the last 15 years, incorporating elements of punk rock, free jazz and modernist composers like Stockhausen. And it's no pose: when asked what's currently on his turntable, guitarist/vocalist/songwriter, Lee Ranaldo, runs through an eclectic ballroom that ranges from German ambient techno outfit, Oval, to Miles Davis.

Their new album, A Thousand Leaves, is a spacious, open-ended affair that will not please those of you looking for a three-minute perfect pop high. Admittedly it can be heavy going at times but that's because it's music that demands to be taken on its own terms; Sonic Youth have never played by anybody's rules but their own. Long, winding passages of noodling guitar suddenly give way to a frenzy of dischord and chaotic white noise before calm is restored and it's off on another tangent they go.

One track ,'Hits Of Sunshine' is Lee Ranaldo's 11 minute tribute to the late bearded Beat, Allen Ginsberg. Did he know the poet well?

"I would say I knew him fairly well for the last five or six years of his life," says Ranaldo. "I probably was the one in the group who knew him the most although we all had chance encounters with him. He would come to shows. We'd hang out now and then. Steve (Shelley, SY's drummer) and I backed him up on a couple of different musical projects he did over the last few years."

Ranaldo acknowledges that the whole Beat movement was hugely influential to Sonic Youth's artistic vision: Ranaldo has contributed to a Jack Kerouac tribute album and he admits the stylistic schizophrenia that is the band's stock-in-trade has as its muse the cut-up technique of William Burroughs.

"He was definitely a huge inspiration," he enthuses. "The general quality of the writing, the muscular enthusiasm . . . I don't know how to describe it . . . I read it when I was younger and it just really struck me. We could talk about it for the next two hours. Kerouac especially. He took me places which I just thought were really cool. This was at the time I was experiencing my first road travel so it had a great resonance."

But the most powerful creative spur to the band when they first started off was the New York punk scene of the late '70s, when the likes of Patti Smith, Suicide, the Ramones and Television were playing to a goggle-eyed CBGBs crowd that included a young Thurston Moore and Lee Ranaldo.

"I remember going to those shows in CBGBs," says Moore, Ranaldo's fellow guitarist/vocalist/songwriter. "Television in particular just blew me away. It's difficult to describe just what an impression shows like that can have when you're a 21-year-old kid. It was so energizing."

It is said that when Suicide played live back in the '70s, the crowd would riot 'cos they couldn't handle the music.

"The riots were on stage," asserts Moore. "Everyone was just staring in silence and trying to take it all in."

With the likes of Spiritualized paying their respects to the recently reformed Suicide and Patti Smith receiving Inspiration Awards from Q magazine, how does Ranaldo feel about the growing critical kudos the old CBGBs stable is receiving?

"People are always playing catch-up," he demurs. "If you ask me, they were far more influential and meaningful back then than they are now. I take nothing away from any of them, especially someone like Patti who I think is incredible, but there's always going to be that thing where people who missed it first time around want it 20 years later. I'm really happy to have been there the first time, that's for sure."

Of course, now the student has become the teacher. Sonic Youth have just completed an American tour in which 30 different acts were invited to play support (ranging from young bands such as Climax and the Golden Twins to jazz veterans like Milford Graves, who played drums in John Coltrane's band). Both Shelley and Moore also have their own labels which they use as a further outlet to help the underground go overground. At this stage, their status as the elder statesmen (sorry, Kim) of the art-rock scene seems secure.

"We're aware of that," says Ranaldo. "We certainly see plenty of bands that show our influence. Those aren't always the most interesting ones but there have been a whole host of bands that have dipped into one or another period in our music. That's been gratifying."

Of course, Sonic Youth played no little part in grunge explosion of the early 90s: it was Sonic Youth who persuaded Geffen to sign Nirvana from Sub Pop, and had they themselves not been on the label, it's doubtful whether or not Kurt Cobain would ever have signed on the dotted line. And it was as guests of the Youth that Nirvana first road-tested the songs that would end up on Nevermind on a European tour that included a legendary gig in the Top Hat in Dun Laoghaire.

"I remember that tour," says Moore. "We played in some city . . . Cork, I think. I remember Nirvana had just gotten a new drummer at the time. I remember wondering whether they were going to be as good because I had been really impressed with the previous one.

"I remember meeting Dave Grohl for the first time in the hotel lobby. He was just sitting there and I was introduced to him. But I'll tell you, after the show that night, all my fears were dispelled. He was incredible and the whole band were right on the money. That tour saw Nirvana at their peak."

Did you have any feeling then that this was a band who could go supernova? "Well, I always thought they were special but then I've thought that about a lot of bands in the past that we played with who went on to do nothing at all!"

Ranaldo concurs. "We knew they were incredible but the amazing thing was how the mainstream picked up on it because they're never usually smart enough when it comes to that sort of thing."

Had you any idea at that time that Kurt was as messed up as he so obviously was?

"Well, not really," avers Moore. "I mean, I suppose looking back on it, it shouldn't really have been that much of a shock because when you listen to the records and what he was singing about - it's all there."

A Thousand Leaves is the first Sonic Youth album to be re-corded in their own home studio in New York, following on from the three uncompromisingly experimental EPs that they released on their own label, SYR (Sonic Youth Records). Is it important for the band to have total control of the recording process when they make an album?

"I don't know if I would say that it was important to us," ponders Ranaldo, "but it's been something that I would say we had been working towards for such a long time and it was really gratifying to be able to make this record that way because it allowed us to completely shift gears, instead of working in a more traditional manner where you write all the material and go into the studio and have to get it all out in a one month period. Then it becomes like some super pressure cooker. With this record, we were able to record over seven or eight months. We could pick and choose stuff and get at the kind of emotional quality we wanted the music to have."

With the band now in their 40s, is it difficult for them to remain motivated?

"It's the easiest thing imaginable," says Ranaldo. "The position we're in now is what we have wanted all this time: we have our own studio and we've got so much stuff that we still want to do. It's almost the opposite of your question. It's not difficult at all."

Do they still check out local bands around the area?

"I find that it's harder and harder for me to get to see shows," answers Thurston, "because, well, I've got so many other things that take up my time nowadays. There's the studio that we've built here and I've got a kid to look after so things are a lot different now. I don't get out much anymore! I guess that's just what happens when you get older. Most people who go to see bands are, on average, teenagers or people in their early twenties. But I check them out when I can."

Did they imagine when they first formed Sonic Youth that they'd be in the same band 17 years later?

"I didn't think about it one way or the other," purrs Ranaldo. "Nobody ever thinks about that kind of stuff. You just plough ahead and deal with the next five months or whatever. You never think about where you're gonna be 20 years from now, especially when you're talking about rock bands: they never last this long."

From Madonna pastiches to anti-Fascist rants; from short, sharp shock to aimless, endless improv, Sonic Youth have covered so many stylistic and musical bases throughout their career. What direction might they take in the future?

"You know, I don't have any idea," ponders Ranaldo. "We try not to conceptualize that stuff. When this touring period is over, we'll just go back to the studio and, depending on what interests us at the time, that's where the music will go. It's kind of hard to say." n

• A Thousand Leaves is out now on Geffen. Sonic Youth play the Olympia Theatre, Dublin on Saturday, 18th July.