Osvaldo Golijov is the new flavour of fusion. And his is a pungent blend: tango and Talmud, Ashkenazi and Sephardi, Arab, Christian and Jewish. The 46-year-old Argentinian composer gathers around him such luminaries as Francis Ford Coppola, the Kronos Quartet — and Dawn Upshaw, who created the title role of his opera Ainadamar, staged by Peter Sellars at Santa Fe last summer.

Wednesday evening at the Barbican marked the world premiere of a sequence of extracts from the opera, called Ainadamar Arias and Ensembles. So many musicians and so much equipment had to be accommodated that the stage management took almost as long as the music itself.

That word Ainadamar means Fountain of Tears — and the reference is to the Granada of Federico García Lorca’s assassination. The opera is about rather more than that; but the sequence of extracts worked pretty well as a shifting frieze of meditations on personal and political sacrifice. Three amplified solo singers — Dawn Upshaw, Jessica Rivera and Kelley O’Connor — wrung their hands and their hearts in a highly coloured evocation of Andalusian rhythm and melody, while members of the BBC Symphony Orchestra (including amplified Spanish guitars, xylophone and tubular bells), conducted by Roberto Minczuk, created a soundtrack of sensuality and violence.

The poetry, the politics, and the impassioned performance of Upshaw were undeniably strong stuff; but the music itself was disappointingly weak. This was little more than a collage of echoes and allusions. So was the score of Ayre, a new 45-minute song cycle for Upshaw and the chamber ensemble, the Andalucian Dogs, receiving its European premiere. Again, the ideas and the inspiration were seductive enough: Sephardic laments and lullabies, Arab Easter songs, and a setting of Yehudah Halevy’s poetry.

But these were second-hand goods. To hear Upshaw putting on a set of vocal disguises in a mere mimicry of some of the most powerful and ancient musics of mankind was at best tedious, at worst risible. Better Golijov’s Tekyah for klezmer clarinet (David Krakauer), accordion, brass and shofars — a truly potent musical ritual, and an eloquent memorial for Auschwitz.

The concert will be broadcast on Radio 3 on Feb 16, 7.30pm