Triptych Festival, various venues, Edinburgh, Glasgow, Aberdeen

From Candi to Karlheinz

"Please close your eyes," says the imposing man in a blindingly white suit as we are slowly and deliberately enveloped in complete darkness. It's not unusual to see the occasional elder iconoclast in the intense musical kaleidoscope that is Triptych, Scotland's wilfully diverse - and increasingly essential - festival of music from the outer edges of pop, folk and electronica, but Karlheinz Stockhausen, the most influential and controversial living composer and pioneer of electronic music, has achieved such mythic status that it is a shock to see him.

"Please close your eyes," says the imposing man in a blindingly white suit as we are slowly and deliberately enveloped in complete darkness. It's not unusual to see the occasional elder iconoclast in the intense musical kaleidoscope that is Triptych, Scotland's wilfully diverse - and increasingly essential - festival of music from the outer edges of pop, folk and electronica, but Karlheinz Stockhausen, the most influential and controversial living composer and pioneer of electronic music, has achieved such mythic status that it is a shock to see him.

In Edinburgh's Queens Hall, a converted church, the 76-year-old German composer, who remains at the forefront of the European avant-garde after 60 years of unstinting experimentalism, genially introduced a performance of his revolutionary 1958 electro-acoustic work Kontakte. Performed in quadraphonic sound along with Octophonie, both pieces are part of an immense body of work which has influenced people from The Beatles to Boulez, from Can to Radiohead, and a contemporary generation of samplers

The sepulchral setting seemed to suit Stockhausen, who sat in the middle of the hall behind a massive mixing console like white-suited godhead, projecting (he doesn't conduct in the traditional sense) music into the air, controlling sounds which ricocheted between speakers. There was something emotionless about the experience, extraordinary though it was. Stockhausen's once revolutionary techniques have been absorbed by the new laptop wizards, such as Mugison and the mighty LCD Soundsystem, who crowded this year's programme. It felt like the future had caught up with the man who helped create it.

Laurie Anderson has seen this future and is not sure is she likes it. She arrived at the same venue for the European premiere of The End of the Moon, inspired by her residency as Nasa's first artist-in-residence.

Essentially another ambient episodic narrative, delivered in the elfin New Yorker's conspiratorial voice, her wry stories - from childhood memories to the jet-propulsion labs in Nasa - are pointed things about human fallibility. Hilarious, calming and scary in turns, she reflected on a post-9/11 American landscape of fear and corporate paranoia.

In another venue, the 67-year-old Prince Buster - who forged the chopping rhythms of ska in late 1950s Jamaica and inspired the 2-Tone label in the 1980s - arrived on stage with outstretched hands. His booming vocals are a little faded now but the dangerous skanking edge of "Al Capone", "One Step Beyond" and "Madness" is the authentic voice of the original rude-boy gangsta-rap, joyous, edgy and overwhelmingly infectious.

The same night another long-lost veteran electrified a sweat-drenched Bongo Club and set the Triptych Festival alight. Candi Staton, following her massive 1976 disco hit, "Young Hearts Run Free", once ruled the world's dancefloors. But a series of abusive relationships and alcoholism sent her spiralling into obscurity. Then she found God and for nigh-on two decades she has sung nothing but gospel.

But, at 62, she has retuned to secular soul music with a vengeance, her honeyed voice textured by a life's travails and honed by the inspiration of religious music. I had expected a perfunctory run-through of an established catalogue, but Staton delivered a full-blown deep-soul show.

Looking nothing like her age and occasional reaching out into the fluttering hands of front-row fans, Staton gave a master-class in smouldering control and explosive release. A surprisingly poignant version of "In The Ghetto"and an extended "Young Hearts Run Free", much grittier and funkier than the poppy disco version, had her leading an ecstatic audience of young clubbers into exhaustion. There was no gimmickry, no resting on laurels or hiding behind backing tapes, just the unfiltered emotion of unfettered soul.