THE EYE: CLASSICAL & OPERA

The Academy of St Martin-in-the-Fields, conducted by Martyn Brabbins, plays Philip Glass in the Royal Festival Hall (0171-960 4242) on 15 May at 7.30pm; then, on 16 May in the same venue, the Philip Glass Ensemble plays music from an eclectic selection of Glass's greatest works

For a contemporary composer with such a cult following who, perhaps surprisingly, celebrated his 60th birthday earlier this year, the music of Philip Glass is still scarce in our concert halls. The reason for this is that it's either lavishly theatrical or composed for his own Philip Glass Ensemble. So these two birthday concerts make amends. In the first, Act II of his seminal opera Satyagraha, inspired by the life of Gandhi, plus his recent Heroes Symphony, derived from the music of David Bowie and Brian Eno, both receive British premieres. In the second, the Philip Glass Ensemble takes to the stage for a rollercoaster ride through Glass's corpus, from Music in Twelve Parts (1971-74) to more recent compositions.

Glass's long career may have evinced him starting out as the archetypal minimalist, though he quickly refutes the notion that he is still repeating himself... in more senses than one. "I think my music has undergone some four or five major changes, usually pinned to a big operatic project," he tells me, "which has often proved transitional. I'd say to those people who think they know my idiom that they maybe haven't heard what I've been doing over the last 25 years."

One thing he has been doing during that time is promoting much of his work through the Philip Glass Ensemble, calling the high-gloss and visceral

sound of the band, his own "instrument". And does Glass himself still relish pounding away at his keyboards? "Absolutely," he says, enthusiastically. "I don't think 60 is old these days. I feel great - this is a very busy year for me and I've got projects lined up until past 2000. But I tend to compose in the winter and summer and tour and play in the spring and autumn, and I haven't lost my appetite for either of those activities."

EYE ON THE NEW

Not a concert but a film. The "work" in question is Karlheinz Stockhausen's extraordinary Helicopter String Quartet, in which the four musicians of the Arditti String Quartet performed live from four different airborne helicopters, with Stockhausen mixing in the noise of rotors as an integral part of the composition. Dutch filmmaker Frank Sheffer captured the one- and-only performance in his 75-minute film, which also includes interviews with composer and performers. Queen Elizabeth Hall, London SE1 (0171-960 4242) today at 5.30pm