At the heart of the musician's creed rests the promise of beatification for all those that listen, for they shall truly move their audience. William Christie and his open-eared ensemble, Les Arts Florissants, have achieved blessed status by holding fast to the listening doctrine, a disarmingly simple faith in ageless musical values practised without deviation throughout their weekend contributions to the Barbican Centre's "Great Performers" series. For once, the marketing epithet was entirely appropriate, with fine works by Charpentier and Monteverdi delivered at a level of intensity and emotional commitment beyond the reach of all but the best.

The wit preserved within Marc-Antoine Charpentier's lightweight entertainment Les Plaisirs de Versailles, written to divert and flatter Louis XIV, was ably translated to suit the tastes of a low-born audience by Les Arts Florissants. Sophie Daneman was elegant, imaginative and beguiling as La Musique, her efforts matched by the panache of Katalin Karolyi, who was delightful as the "prattling divinity", La Conversation. Daneman has developed the self-confidence necessary to resist any temptation to push her voice in a hall of Barbican proportions, wisely shading and projecting her natural, very beautiful tone and cherishing every word and phrase in a way that here commanded attention.

The soprano's brief but unforgettable contribution to Charpentier's take on the Orpheus myth, La Descente d'Orphee aux Enfers, caught the full tragedy of Euridice's death, especially so in her tortured final cadence. The austere semi-staged presentation, powerfully handled by Ana Yepes and graced by her solo dances, underlined the composer's sense of theatre, never more persuasive than in Orphee's heart-breaking negotiations in Hades. A general riot would have risen from the stalls if Orphee's haunting intercessions had been rejected by Nathan Berg's rich-voiced Pluton, Paul Agnew pleading the case for Euridice's return with a compelling mix of intelligence and raw emotion.

For the ensemble's brief programme of Monteverdi madrigals, the gold standard set by Daneman, Agnew and Berg in the Charpentier works remained unadulterated, if anything strengthened by the corporate desire of the musicians of Les Arts Florissants to have a good time. Christie's continuo group sounded as one with his singers, adding an extra range of tonal colours to the available palette and providing the perfect background for the clear delivery of words. The composer's "war-like" sounds were boldly sung and played, and even converted into pantomime actions by the male trio in "Gira il nemico". Here, Nathan Berg gave a fair impression of Nathan Detroit and his loud-shirted accomplices suggested further parallels between Monteverdi's amorous song and a chorus from Guys and Dolls.

Physical and vocal gestures of a more subtle but no less theatrical kind marked the group's powerful account of Il combattimento di Tancredi e Clorinda, expressively narrated by Paul Agnew and adorned by Ana Yepes' poignant choreography.

The polish put on these performances was not of the remedial consistency so often applied to cover flaws in preparation, but rather served to highlight the craft and musicianship of Christie's band. Above all, it allowed the full meaning of each text to register clearly, every aspect of sadness and joy, love and anger reflected in the shaping and colouring of phrases.