Bang on a Can, Barbican Hall, London <br></br>Daphne, Royal Opera House, London

New York in the spring of 1997, my first visit. I never made it to the Met but these were halcyon days. I heard lieder in a SoHo loft, punk in a former synagogue, met a woman who made music with balloons, and heard the Bang on a Can All-Stars for the first time. I don't recall the programme but, like much in that month at the nexus of experimental art and music, it seemed like pure sunshine. So why – five years later, on a rainy evening in London – did New York's leading contemporary music virtuosi have the opposite effect? Is holiday fan-ship as fickle as holiday friendship? Had I fallen foul of the rigid stylistic genres that Bang on a Can profess to ignore? (Their concert was advertised as part of the Barbican's Jazz Series.) Or is a programme where Tan Dun provides the only interesting thematic development a programme with a problem? Yes, Bang on a Can can whirl and swirl and twirl, but all the technical virtuosity in the world cannot compensate for a lack of musical substance. Unless, that is, characterless incidental music to made-for-TV surrealism – Don Byron's Eugene, written in tribute to The Ernie Kovacs Show – is your cup of ginseng.

Bang on a Can's reactionary modernism might be standard fare for fans of avant-garde jazz (I wouldn't know) but it's hardly reflective of contemporary art music. New Work, Cecil Taylor's, er, new work, proved loud and pretentious. (What can you say of a piece that uses a U-bend with a saxophone mouthpiece, involves a lot of snarling and jumping around and could have been designed by the writers of The Fast Show?) But the most striking aspect of this programme was how the one work that worked was the one that fully exploited the artistry of its players. (By which I mean a more complex form of artistry than displaying a degree of physical flexibility and daring more commonly associated with tantric sex.) Whatever misgivings one might have about Tan Dun's crypto-conservatism – Concerto for Six owes a heavy debt to neo-classicism – this was a piece that required more than mere posturing. In the extravagant solo passages between Dun's tango-esque ritornelli, each player had space to colour their notes, revealing the idiosyncrasies of Bang on a Can's current line-up. Though multi-instrumentalist Mark Stewart did remarkable things with plumbing materials and a guitar and Robert Black wrestled, dragged, slapped and waltzed his double-bass into near coital flights of harmonics, only cellist Wendy Stutter managed to negotiate the oppositional demands of gymnastics and tone and add a blush of beauty to her line. Clarinettist Evan Ziporyn, percussionist David Cossin and pianist Lisa Moore showed themselves to be fine technicians and thoughtful ensemblists – with the exception of Concerto and Ziporyn's knotty arrangement of Hermeto Pascoal's Arapua, that was all they were allowed – but Stutter's refusal to let sounding a note be the end of that note stood out in an evening that was otherwise more about facility than art.

Organic, trellised and splintered through a prism of breathtaking harmonic intricacy, Strauss's 1938 one act opera Daphne is as overwhelming as it is intoxicating – which might better explain why it's so rarely staged than the standard excuse that you can't convincingly transform a soprano into a tree. Of course there are plenty of singers of whom one would barely notice this metamorphosis, but Alexandra von der Weth – the eponymous nymph in Covent Garden's two concert performances – is not one of them. In an evening overloaded with talent – James Rutherford (First Shepherd), Roberto Sacca (Leukippos) and debuting conductor Stefan Soltesz to name but the very best – von der Weth combined the crystal clarity of Janowitz with the lyrical wistfulness of Popp. So her diction is diffident and her phrasing sometimes squeezed? This a woman who not only sings like a dream but looks like one – a voluptuous chimera of Monroe, Ekberg and Jerry Hall – a woman only matched by a man-mountain with hockey-hair and a truly heroic tenor voice: the wonderful Johan Botha (Apollo). Off-stage they'd make an unlikely couple. In concert they were transcendent. But this – plus the pleasure of finally seeing the Royal Opera House's normally invisible orchestra – is one of the joys of concert performances: there are no distractions and no anachronisms. That the applause for this was the longest and loudest I've heard at Covent Garden was only fair.

a.picard@independent.co.uk