Festival Simon Bainbridge / Kurtg Pump Room, Cheltenham

One might imagine that Simon Bainbridge would have exhausted his Primo Levi vein in the overwhelmingly intense settings he made with orchestral accompaniment last year (the BBC commission, Ad ora incerta). But something was evidently left unsaid. And this has now borne fruit in a new cycle of Four Primo Levi Settings, written for the Cheltenham Festival and premiered there very impressively by Susan Bickley with the Nash Ensemble in the Pittville Pump Room last weekend.

Some composers escape from overpowering impressions into their opposite: the lightweight or abstract. Bainbridge has simply written four more songs of the same dark graphic intensity as before. But where Ad ora incerta was spread over a huge orchestral canvas, this new piece is chamber music. The mezzo-soprano is accompanied by the Mozart "Kegelstatt" trio of clarinet, viola and piano, and the instrumental colouring is as spare and astringent as it was previously rich and saturated. There is an intimacy - a privacy - which the old cycle avoided. One of the songs is even reduced to voice and viola, without any feeling of inadequacy, and in all four songs Bainbridge is able to keep the vocal setting discreet and inward - part of the texture, almost at times a subtext to it.

These are again beautiful if draining pieces, 15 minutes or so of exquisite gloom, sustained with real mastery, decorative but never straying into the picturesque. Perhaps there is nothing here quite so striking as the images of the crow and the departing train in Ad ora incerta, but nor is there that quality of surfeit which one might find exhausting in the earlier score. The inward is rarely as exciting as the outward; but it may be at least as near to the truth.

The Bainbridge cycle was the first of a series of chamber music novelties in Michael Berkeley's admirably diverse, undoctrinaire festival. Annoyingly, I couldn't get to Robert Simpson's new one-movement string quintet (for the Schubert combination) on Thursday. But I can confidently speculate that it had little in common with Kurtg's Signs, Games and Messages, which the Leopold String Trio included in their Friday morning concert in the Pump Room. Kurtg's mysterious, teasing brevity and gestural violence are a long way from the linear discourse which remains basic to the two otherwise quite different British composers. And they can raise difficulties which the young players of the Leopold Trio sometimes did, sometimes did not, fully solve.

The genealogy of these 17 pieces is obscure. Some of them seem to be revisions of an early work called Signs for solo viola, others are much more recent. But their coherence as a set is in any case artificial, achieved as much as anything by internal reprises; and I suspect that, for one thing, the set is not complete but merely a selection and, for another, its order is provisional.

It hardly amounts to a string trio anyway - perhaps unfortunately, since the actual trio pieces are brilliantly effective but, of course, too short and too few. What wouldn't one give for a real string trio by Kurtg! The other pieces form solo cycles for each instrument (there were no duos on show). And these are typically bizarre, arcane, impish, and with enough ideas, one would think, to make a lifetime of neo-Bach partitas. The whole work was played with polished musicianship, if not quite enough manic abandon, and it was evidently hugely enjoyed by a very respectable Cheltenham audience.

The Cheltenham Festival continues to 21 July. Booking: 01242 227979

STEPHEN WALSH