Le Concert D'Astree/Emmanuelle Haim, Barbican, London

Is it possible that Natalie Dessay is allergic to the Barbican? Billed at least three times to appear, she has yet to grace the stage. Cancelling on the day of the concert is a bit rough on everyone, but into the breach sprang the English soprano Amy Freston, who made a more than decent fist of her sudden propulsion into the shoes of Dessay, recently named in the British press as "singer of the year".

It is the time of coughs and colds after all, but Emmanuelle Ham, conducting her crack baroque ensemble, Le Concert d'Astre, must have felt a bit jinxed, having only days before also lost a tenor to be replaced, fortunately, by the greatly experienced Paul Agnew.

Whether these trials had an undermining effect or not, this potentially special concert turned out to be merely respectable. Two great works of the Baroque, Handel's Dixit Dominus and J S Bach's Magnificat shared the (very short) bill, as they did the very real technical difficulty of two composers writing instrumentally for the voice.

This is cruel stuff to articulate; it's one thing for strings to play rushing scalic passages but quite another for the voice, even if it is supposed to show off the prowess of the singer.

The splendid Concert d'Astre chorus articulated Handel's opening number like gun-fire, spitting out the words. Pace, in the faster numbers, seemed to be Ham's thing, at times only just maintaining adequate control. Tim Mead, alto, negotiated his highly decorated aria with scarce vibrato and only the occasional hint of a hoot. But Freston and the soprano Salom Haller were ill-matched vocally, Freston fresh and sweet, gently shading her dynamics to Haller's more strident tone in Handel's fine "De torrente".

With the orchestra expanded to include winds and those fabulous D trumpets, it was odd that Bach's joyous opening felt studied rather than joyful. Freston was most touching in her aria with oboe d'amore, while Mead and Agnew spun an exquisite "Et misericordia" to muted strings and flutes. Robert Gleadow, bass, was both clear in pitch and agile of voice. But Ham seemed strangely distant from her vocal soloists.