Music; Wihan String Quartet Wigmore Hall, London

The weather is usually irrelevant to musical appreciation. Yet, when the thermometer plunges below freezing, merely turning up at the Wigmore Hall provokes an inner flush of self-esteem. Bravely performing on the Thursday after Christmas, the Wihan Quartet drew a full audience whose applause was partially (and forgivably) for its own fortitude. Yet there was also genuine praise for much fine playing, rewarded by a pair of encores from Dvorak and Haydn - the finales of the "American" and "Lark" quartets - to return the connoisseurs to the cold with a tonic of robust good humour.

Winners of the 1991 London International String Quartet Competition, the four players used the first piece, Schubert's C minor Quartettsatz, to announce the kind of confident rapport to be expected from an ensemble that's been around since 1985. In fact, the confidence seemed too embracing, for the stormy mood of this most intriguing of Schubert's unfinished musical torsos was at times sedated by urbane phrasing and a sense of knowing too much. When the music lurched flatwards in typically Schubertian style, their shared sense of unison phrasing was impressively dramatic. Elsewhere, more fire and brimstone from the seat of the passions would have kindled real ardour, rather than an elegant despair that called to mind the polish of a composer like Saint-Saens.

To follow, Mozart's "Hunt" Quartet and Dvorak's G major Op 106 brought the breath of summer melodies to thwart winter's cold embraces just beyond the door. For the Mozart the ensemble chose pert tempi, with the smooth- toned cellist Ales Kasprik a binding force amid the trills, turns and shakes of the first movement. Thereafter, a stroppy Minuet progressed to the tick-tock Trio with a sense of ineluctable purpose; and from there to the broader goal of the serene Adagio, whose opening sentence, shapely and resounding, displayed the finest playing of the evening. A sequence of melting chromatic chords - Mozart stamped all over them - also drew qualities of exquisite taste and presentation from the players.

Moments such as these were touchstones of the Wihan collective skill, to be savoured all the more in contrast to their low-pressure Dvorak. Despite their reserves of native verve, this was a curiously unsatisfying reading, if not lacking in fine incidental detail. The glorious tunes of the first movement reappeared in different settings that the quartet coloured with orchestral richness: the cunning textures that opened the slow movement even suggested deep, slumbering orchestral horns.

Here, perhaps, lay the root of the problem. For while the three lower instruments excelled at backing and accompaniment, the first violin took possession of the score in a way that displaced the chamber-music ideal. The rowdy finale solved the problem on its own terms, the instruments locked in incessant dialogue between upper and lower strings. Clearly, the Wihans enjoy fast music of this kind: light and buffa in their hands. Even so, they should remember to listen to each other without loosing their nerve.