It's testimony to the programming of the Huddersfield Contemporary Music Festival that it resists the temptation to provide glib answers to questions of music's millennial development. Instead, with debuts by Chinese ensembles alongside premieres from Georges Aperghis and Guo Wenjing, the thread running through the whole programme is an enthusiastic eclecticism.

But there is, as ever, a commitment to the composers and performers of the avant-garde. And few groups can claim to have had the same seismic impact as the Arditti String Quartet. Their pairing of quartets by Schoenberg and Ferneyhough was a stunning distillation of modernism's achievements. Schoenberg's Second Quartet is one of those rare pieces in which the development of a musical language is dictated by expressive necessity. Setting Stefan George's poem Rapture, with its opening line "I feel the air from another planet", Schoenberg's music transcends tonality and creates an extraterrestrial soundscape

Ferneyhough's Fourth Quartet follows Schoenberg's example in its use of a soprano. However, the challenge for Ferneyhough is not the creation of a new musical idiom, but a reconciliation of the collision between music and language. Ferneyhough's music veers between long-breathed lines and fractured gestures, while the singer inhabits a dislocated region somewhere between speech and song.

Ferneyhough's attempt to unite language and music is necessarily doomed, and the quartet ends with a monologue of phonetic deconstructions for the soprano - as if the players have failed to make their scarified music achieve a linguistic articulacy. This tortuous struggle demonstrates that the 20th century's search for new musical worlds, epitomised by the final movement of Schoenberg's 1908 quartet, continues unabated.

Among the younger generation, the Berlin-based British composer Rebecca Saunders has found a fascinatingly distinctive voice. In Crimson Molly's Song I, Saunders incorporates whistles and music boxes within the work's finely balanced textural tapestry. Expertly negotiated by Lontano and Odaline de la Martinez, these "sound objects", as she puts it, become just another ingredient in the piece's sonic palette.

But these "objects" also represent an elusive set of extra-musical associations. And that's the compelling feature of Saunders's music: each work is both a self-contained world of sound gestures and a place of fantastical imagination. In Duo 3 for viola and percussion, premiered by soloists from Psappha, Saunders pares down her compositional material to the point of austerity. At times the music seems to slip out of its keenly conceived framework into the realms of non-intentional sound, like a whole series of pre-existing "objects".

The music of 80-year-old Galina Ustvolskaya rings out like a dark bell over the terrain of contemporary music. Reinbert de Leeuw and the Schönberg ensemble performed her set of Three Compositions for wildly unusual instrumental combinations. The obsessive, ritualised intensity of No 2, "Dies Irae" for eight double basses, wooden box and piano, was magnified by the grim theatre of the percussionist hammering at his coffin-shaped instrument. Ustvolskaya's music is uncompromising and shattering - a vindication of the possibility of expression in a wearily postmodern culture.

• The festival continues until Sunday 28. Details: 01484 425082

***** Unmissable
**** Recommended
*** Enjoyable
** Mediocre
* Terrible