Zehetmair Quartet, Wigmore hall, london

Under the leadership of the charismatic violinist Thomas Zehetmair, the Zehetmair Quartet have won a string of awards for their recordings of Schumann, Hindemith and Bartok. They only tour one or two programmes a year, but play their full repertoire from memory. Presumably, the idea is that this will enable the players to interact more spontaneously. Alas, on the evidence of this Wigmore Hall concert, it conduces rather to mannerism and eccentricity.

The overblown way in which they presented Haydn's "Emperor" Quartet sounded almost like a rewrite by Korngold. This is a "big" quartet, to be sure, composed not for a private circle of connoisseurs but for the London concert hall, and its textures are correspondingly full. But the sudden and extreme contrasts of dynamics, the swoops and swoons of expression, the incessant little pullings around of tempo that the Zehetmairs imposed upon it seemed almost nothing to do with the Haydn spirit.

Their rendering of the outer movements of Bartok's String Quartet No 5, by contrast, was spontaneous to a fault: full of gypsy "temperament", if at the cost of much scrambled detail. Yet the Zehetmairs' chill poise and often exquisite refinement of dynamics and coloration in the nocturnal second and fourth movements reminded one that these players are consummate technicians.

Their promotion of those Cinderellas of the classical quartet repertoire, Schumann's three Op 41 string quartets, has also been admirable. How on earth, one wondered, as the first two movements of the Quartet in F unfolded, could music so sunny, so inventive, still be something of a rarity (even if the Zehetmairs did their best to smother the beguiling opening of the work in vibrato)? No doubt the awkward writing of the scherzo, reminding us that Schumann was no string player, is part of the answer.

Curiously, it was the second movement of Hindemith's String Quartet No 4, thrown in as an encore, that found the Zehetmairs at their best. A kind of grey, grinding sub-Bartok rampage needing, responding to, just the sort of colourful quirkiness in which these players seem to specialise.