Classical CHELTENHAM FESTIVAL Round-up

This year's Cheltenham International Festival of Music kicked in with a rapacious tango. Cafe society through a glass darkly, a bevy of saxophones, whinnying violins, and the curdled, hyperactive harmonies of post-Wagnerian angst. Thomas Ades's first opera, Powder Her Face, contained enough music for several Cheltenham festivals. Watch this space for the full story as it moves south to the Almeida. Meanwhile, on the morning after the night before, even Cheltenham's Pittville Pump Room was no place for those of a genteel disposition. The Arditti Quartet were in town and down to earth after recent airborne excursions with Stockhausen. And even their Bach was disquieting.

The Ardittis live for the uncompromising. They're an intrepid, all-or- nothing-at-all kind of group, hungry for the shock of the new, never happier than when subjecting their instruments (and audiences) to a little grievous bodily harm. Composers know to challenge them. But the challenge of Bach's Art of Fugue - unadorned, unvarnished, no vibrato, no cover, just the sound of old voices, parched but true - lies almost entirely in the security of the bowing and tuning, and for the first but not the last time in this hugely diverse and demanding programme, it surprised me just how vulnerable, indeed fallible, the Ardittis could be.

It's partly that the level of musical interest and engagement tends to wane when they're not actually living on their nerves. For my money, they didn't even begin to explore the sensuous half-lights, the subtleties of touch and inflection that are the life-force of Ravel's Quartet in F, while I'm not sure that even Stravinsky, who once described Beethoven's Grosse Fuge as "contemporary for ever", could have imagined it pitched quite this ferociously into an uncertain future. A few unintentional harmonic collisions (the leader, Irvine Arditti, really must watch his intonation) only served to accentuate the extremes.

None of which was of any concern when Xenakis's Tetras sent bow-hair flying in a swarm of buzzing, whining, shrieking glissandi and tremolandi. Just imagine yourself inside the head of a deathwatch beetle as it gnaws and scratches and scrapes its way through the fabric of its environment. That's how it is inside this piece. Alongside Xenakis's wild (and highly personal) elementalism, James Dillon's String Trio (here receiving its British premiere) sounded like so much mathematical theorising. Rather like the composer's programme note, in fact. Both works end by vapourising into the ether. Except that, in the case of the Xenakis, only the sound has vanished.

Farewells - so many farewells - are at the heart of John Woolrich's Viola Concerto, receiving its world premiere later in the day. Just a song, or songs, at twilight is too easy a description for this rather beautiful piece. We do not go so quietly into that long night. We drift on a sea of sorrow, now calm, now unsettled, resisting the tides, a serenade on course for the Isle of the Dead, where a simple horn ritornello can be strangely reassuring and the tolling of gongs and deep undertow of bass- drum represent not so much the threat, more the promise of impending mortality. The melismatic solo part - expressly tailored for the eloquent Paul Silverthorne - makes real capital of the instrument's hermaphroditic colour and character, the orchestral texture is late Mahler, late Tippett, late everything. A direct quote from Tristan ("No ship there on the sea?") is one of several musical reminiscences on which the soloist must ultimately (and quite literally) turn his back. Rest assured, we would not be turning our backs on Yan Pascal Tortelier's blistering account of Sibelius's First Symphony. The BBC Philharmonic were on cracking form.

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