He's in town to promote the latest in a seemingly inexhaustible series of releases that includes, at the last count, no fewer than 11 operas, at least one of five-hour duration, and a bulging curriculum vitae of film, dance and world music collaborations. This time, the collaboration is slightly one- sided, Glass having taken three pieces from David Bowie's landmark Low album from the late Seventies and used them as the springboard for his own 'Low' Symphony.
It's a record that is likely to come as something of a shock to fans and detractors alike, despite the composer's frequent contact with the pop world (his most commercially successful album, the quarter-million-selling Songs from Liquid Days, was a collection of collaborations with lyricists such as David Byrne, Paul Simon, Laurie Anderson and Suzanne Vega). As he takes pains to point out, the new record is not a Boston Pops-style orchestral arrangement of a few pop tunes; it's a full-blown symphony, and one of the least 'minimalist', most traditional pieces he's done. For, while Glass's earlier minimalist works sometimes required steel- willed powers of concentration and maybe a packed lunch to see the listener through, the 'Low' Symphony is so easy on the ear that it could slip in quite nicely alongside the Goreckis and Bachs of Classic FM.
Glass himself likens his adaptation to Bartok's treatment of traditional Hungarian folk dances, but with pop music acting as today's folk music equivalent. 'People who write concert music are actually doing this all the time,' he claims, 'finding a bit of music they like and transforming it into something else - Stravinsky, Bartok, Hindemith have all done it.'
The impetus for the project came as Glass was concluding a series of boundary-bridging world music collaborations with the likes of Ravi Shankar and Foday Musa Suso, though the idea had apparently been long in gestation.
'I remember hearing Low in 1977 and thinking, 'Gee, that's a really nice bit, I think I could do something with that' and putting it to the back of my mind,' he says. 'Then last year it seemed I could finally get around to doing it as a symphonic piece. I remember calling up David about a year ago and telling him about the idea. We had met in the Seventies and stayed in touch off and on over the years, and kept up with each other's music. He liked the idea, and suggested there was other music I might listen to, like Lodger and Heroes, but I really felt I should stick with Low - I also thought that if Low goes well, I could do another symphony based on Lodger. Why blow it all on one record?
'There was a lot of good material on Low: I concentrated on those instrumentals which were in those days on the second side; what I liked about them was that they were clearly experimental, going beyond the formulae of pop music. It was this funny world of art-rock, which has since disappeared, but which was a beautiful moment for a while: the people who were working in experimental concert music and those working in experimental pop music were looking over each other's shoulders at that time - we all knew each other's work.'
Glass first met Bowie and Brian Eno, the Thin White Duke's collaborator at the time, when the latter was working with Talking Heads and The B-52s in New York in the late Seventies, but the connections between them can be traced back even further, to the early Seventies, when the Glass Ensemble played one of its earliest London concerts.
'I did a concert at the Royal College of Art in 1971,' he recalls, 'and David told me some time later that both he and Brian were at that concert. I wasn't welcome in the concert halls in those days, so I played in art galleries and museums and art schools.
'As a result, a lot of people in the art world knew my music, and that's where my audience was. Nowadays, David's in and out all the time, he's always flying around: I remember seeing him at concerts of mine in the Eighties, and whenever he was there we'd get together, say hello and talk a little. We have an easy relationship in that way: I can pick up a phone and talk to him - if I can find out where he is, that is.'
The three pieces Glass chose from Bowie's album come from the second, 'difficult' side: 'Subterraneans', 'Warszawa', and 'Some Are', which wasn't released until the recent CD reissue of Low. It's this latter track that Glass takes the greatest liberties with, and which furnishes him with his greatest success.
'David was surprised by that, too,' he acknowledges. 'I said, David, I hope you didn't mind what I did with that - but he was delighted by it. The original 'Some Are' was very dreamy, with very modal harmony. I took that original melody and re- harmonised it. I found completely different harmonies, and by doing that I found that it seemed to go at a different tempo, about double the tempo of the original. So from being something very dreamy and laidback, it becomes kind of a footstomping Brucknerian scherzo. I took the first minute and a half of his music, then moved into my own: the trick was to move seamlessly from Bowie to Glass, so that you wouldn't know which was his and which mine.'
However seamless the transition from Bowie to Glass, however, the new symphony is a whole (new) world apart from the original recordings, which he acknowledges were very strange and dark pieces, befitting the time and place of their composition.
'But going back to it now, the darkness is gone in some ways,' he believes. 'The symphony has mellowed in the same way that everyone has: I also don't stay up till three in the morning any more. Life looks different when you're in your fifties than when you're in your thirties, and I think that looking back at that music 15 years later, it was bound to have a different emotional colour to it.'
In particular, compared to the bleak despondency of the original, there seems to be a peculiarly optimistic, American cast to the symphony.
'It does sound like that,' Glass agrees. 'Especially the end of the first movement; people say they can hear Copland and Bernstein in it, and I think that's true. Of course, it's bound to be like that in a way; after all, the 'Low' Symphony is a marriage - it's not just a portrait of them, it's a portrait of me too. It would have been strange not to have left my own mark on it. That's what you do when you're a composer and you like something - it's your way of saying, I wish I'd written that, and so you do the next best thing, you change it into something that you would have written, had it been yours.'
'Low' Symphony is available on Point Music / Philips 438 150-2