With special guest Michael McClure. An International Arts Initiatives presentation, in association with the Chan Centre for the Performing Arts and the LIVE Biennial of Performance Art. At the Chan Centre for the Performing Arts on Friday, January 20

I'm still puzzling over what, exactly, I saw and heard at the Chan last Friday, and so, I suppose, are many other long-time admirers of pioneering minimalist Terry Riley and Beat icon Michael McClure.

If the two artists were trying something new, the experiment failed. If they were consciously trying to summon up past glories, then their performance offered up a time-capsule look at California cool, circa 1966. And if they were just winging it, then they deserve some kind of appreciation for staying true to their experimental roots, although a more formal presentation might have done their material greater justice.

Even so, the first part of the program was sloppy, perplexing, and nearly devoid of musical, if not poetic, interest.

The concert began promisingly enough, with Riley singing a traditional North Indian raga backed by his own piano accompaniment. The 70-year-old composer is one of a handful of western artists who have mastered this intricate idiom, and although his voice is starting to creak with age, his commitment to the form remains admirable.

But things fell apart when McClure joined him. This contemporary of Jack Kerouac, Gary Snyder, and Lawrence Ferlinghetti looks extremely youthful for his 73 years but appeared distracted nonetheless, losing his place more than once and eventually walking off in what appeared to be a bemused state. Even McClure's selections from his Ghost Tantras-one of the sacred texts of sound poetry-failed to connect, with Riley adding cocktail-piano tinklings to the poet's world-weary patter.

Understandably, a fair number of listeners left at intermission-but those who did might have made a mistake. After a silly and vaguely Ethiopian-sounding blues from Riley, the veteran composer moved from piano to synthesizer as a newly ener?gized McClure emerged to read his vernacular interpretation of the 17th canto from Dante Alighieri's Inferno. This was not without its absurdities, notably Riley's attempt to inject some entry-level programmed beats into the proceedings. But for the first time in the evening the combination of voice and keyboard added up to more than a Beat cliché; temporarily, at least, we were taken to the very edge of hell, complete with loathsome crawling creatures, shuddering percussive soundscapes, and the moanings of the damned.

And then we were deposited back into a different kind of purgatory, in the form of a cool-bop take on Kerouac's Mexico City Blues-a work that was groundbreaking in its time, but that has been so badly and so often imitated that its freshness is all but gone.

Were McClure and Riley just having an off night? It's hard to say. Based on earlier interviews, they have a genuine respect for each other, and both were enthusiastic about their collaboration. On this occasion, how?ever, their vaunted chemistry was in short supply.