Yo-Yo Ma/Ton Koopman/Amsterdam Baroque Orchestra, Barbican Hall, London<br/>London Symphony Orchestra/Valery Gergiev, Barbican Hall, London<br/>Gruppen, Blackheath Concert Halls, London

Yo-Yo the magical time traveller

For those who've avoided record shops for the last few years, Yo-Yo Ma's latest project may come as a surprise. But his has been a career of constant revolution and reinvention: encompassing recitals, recordings and concertos, experiments in Jazz, Tango and American and African Folk Music, appearances in The Simpsons and The West Wing, coinage as an expression of erotic appreciation in Seinfeld, collaborations with film director Atom Egoyan and choreographer Mark Morris, an ongoing interest in the music and culture of The Silk Road, and, most recently, a flourishing partnership with arch-authenticist Ton Koopman, the Amsterdam Baroque Orchestra and a gut-strung 1712 Stradivarius.

For those who've avoided record shops for the last few years, Yo-Yo Ma's latest project may come as a surprise. But his has been a career of constant revolution and reinvention: encompassing recitals, recordings and concertos, experiments in Jazz, Tango and American and African Folk Music, appearances in The Simpsons and The West Wing, coinage as an expression of erotic appreciation in Seinfeld, collaborations with film director Atom Egoyan and choreographer Mark Morris, an ongoing interest in the music and culture of The Silk Road, and, most recently, a flourishing partnership with arch-authenticist Ton Koopman, the Amsterdam Baroque Orchestra and a gut-strung 1712 Stradivarius.

Consider the synchronicity of Yo-Yo Ma's career and the growth of historically informed performance practice. So tightly bound are the timelines of each that their convergence seems inevitable. Then imagine those first, delicate, dove-grey notes of Haydn's D major Cello Concerto, their shy, antiqued-silver glow, and the rapt atmosphere of a Barbican audience holding its breath with unanimous astonishment at the latest incarnation of this chameleon cellist. The soundworld may be different, the bow may be shorter, the tail-pin absent, the strings more porous and vulnerable but the most fascinating aspect of Yo-Yo Ma's gut string playing is how little it differs from his modern style. The blanched, extended notes are slower to be intensified with vibrato, the decorations are more languorous and French-accented, and the colours are subtler, cooler, more blue of tone. Yet the musical character - open-minded, alert, inquisitive, relaxed - is absolute, be it in the poised reflection of Vivaldi's C minor Concerto for Cello and Violins, or Haydn's more robustly genial work. The touchstone here was Haydn's sonorous interweaving of lower strings: an intimate chamber music quality that allowed ABO's firm, distinct viola section to assert themselves to delicious effect. Give or take some Romantic twists in the cadenzas, Yo-Yo Ma knows well when to background himself and the most infectious aspect of this extraordinary performance was in observing the pleasure and inspiration he drew from an orchestra composed of period specialists. In the Adagio, his musical connection with leader Margaret Faultless bordered on the carnal, while his dialogue with principal cellist Jonathan Manson was a model of mutual respect and admiration, justly celebrated in a ravishing encore - their third - from Vivaldi's Double Concerto. Amsterdam Baroque's performance - in the concerti, in Haydn's Symphony No 83, and in a brief selection from Handel's Water Music with trills to die for from the horns - was stunning enough to dispel any hint of contempt for familiar repertoire. Koopman's direction and continuo playing was generous, lively, rich and stylish throughout. A revelation in every respect.

One Baroque blip aside, the Barbican was this week otherwise given over to Valery Gergiev's tour of the complete symphonies of Prokofiev with the London Symphony Orchestra: the latest micro-festival in the LSO's impressive centenary season and another collaboration that brought out the very best from all concerned. But there the parallels end. Though I marvelled at the technique and commitment of players and conductor during their performance of Symphonies 1, 4 and 5, I cannot say that I understand this clever, shallow, cinematic repertoire any better for having heard it played so well. Technically, this was a dazzling performance, with blistering articulation from the strings and woodwind, shockingly direct, muscular work from brass and percussion and powerful, intelligent, passionate and controlled direction from Gergiev. But I am still uncertain as to Prokofiev's motivations in the light of his hokey-cokey relationship with Soviet Russia and, if anything, am even more unconvinced of the seriousness or sincerity of his symphonies.

Which leaves but a whisker to commend the 100 assorted students from the Royal Academy of Music, the Royal College of Music, Trinity College of Music and Guildhall School of Music and Drama for their exciting, if nerve-wracking, self-promoted and motivated performance of Stockhausen's polychoral masterpiece Gruppen: the surround-sound listener's equivalent of being one of Jackson Pollock's canvases, mid-painting. Money was raised (for Arts and Kids), weight was lost (by the three intrepid student conductors, Tim Henty, Andrew Morely and Dominic Grier), the Blackheath Concert Halls were full to capacity, and I got to feel really, really old. Who says students are lazy? Not me.

a.picard@independent.co.uk