The Beat plays on

Susanne Stanzeleit & Gusztav Fenyo

St John's Smith Square

If it's possible to be an unobtrusive virtuoso, then the young German- born violinist Susanne Stanzeleit fits the description. Her recital with the pianist Gusztav Fenyo at St John's Smith Square on Thursday was to celebrate the 60th birthday of the composer Janet Beat, and Beat's Vincent Sonata and Violin Sonata No.2 put Stanzeleit through almost every imaginable technical hurdle. Vincent Sonata, for violin alone, is a triptych inspired by Van Gogh's paintings, the last movement a bombardment of multiple stoppings, pizzicato and all kinds of bowing techniques. It was played immaculately, with a selfless concentration, not showily. Apparently, it wasn't performed until long after its composition nearly 20 years ago, because it was so difficult.

Beat wrote her second sonata, with piano, last year. Its three movements make heavy demands on the pianist, who gives the first a tempestuous sense of direction, and recalls its material in the belligerent final section of the last. Fenyo didn't drown out his partner and their ensemble in this new work seemed perfect. But despite its air of being in deadly earnest, the music seized too many opportunities for short-term rhetorical effect to complete a bigger picture. Nor did I get the impression of a strong composer's personality.

Strong is hardly the word, either, for Debussy's Violin Sonata, his last completed work. But that's because of a kind of resilience which is almost sneaky - that strange, transposed repetition of a passage immediately before the burst of determination which ends the work, for example. Fenyo's sensitivity in listening to himself, his ear for exactly balanced sonorities and delicate resonance, and Stanzeleit's precision, clean intonation and perfect bow control, these gripped attention throughout music which can sound, in an indifferent performance, like scrappy whimsy.

The Debussy ended the first half, which began with Brahms's G major Sonata. It was odd to put it there, because its character needs the listener to be prepared - and this was an uncommonly sensitive performance, exquisitely sweet, yet a shade fragile. It really needed stronger projection in this building.

Stanzeleit and Fenyo are certainly capable of packing a punch, for, to end the evening, they were joined by the clarinettist Michael Collins in Bartok's Contrasts. In terms of confidence and security of style, this performance reaped the reward of all the work they must have put in for the CD, and Collins was in shining form. What a shame so few people were there to enjoy it.

Adrian Jack