It has often been remarked that 18th-century scientific instruments are like works of art. Cosi Fan Tutte is a work of art designed like a scientific instrument - a classically proportioned precision mechanism in which music and drama attain an ideal match of form and function.

Tim Albery's Opera North production expands the metaphor by encasing the action in a monumental piece of antique lab equipment. Peter Savidge's wry, dry Don Alfonso is first glimpsed buffing up the lenses of this magnificent casket, which then explodes to reveal the objects of his experiment - the inconstant sisters and their incredulous suitors, literally poised under the microscope.

Designer Tobias Hoheisel's enormous optical wendy house enables the action to be examined from the perspective of a delightfully voyeuristic Enlightenment peepshow. The emotional subtleties of the work are mercilessly focused, while the box-of-mirrors conceit helps to explain the curious distortions of a work in which women fail to recognise their boyfriends after the intervention of a curious 24-hour-long war.

If Albery's concept is aesthetically ravishing, the musical satisfaction is not far behind. Conductor Yves Abel is as inspiring as any maestro Opera North has had in the pit; and the orchestra responds with a world class performance. Special credit goes to the horns, for whom a production of Cosi is always cause for sleepless nights.

Abel has a fine sextet of principals to conduct and, apart from a stray moment in the first act finale, all are secure and impressive throughout. Iain Paton's Ferrando is particularly mellifluous, and Roderick Williams's Guglielmo darkly handsome in both deportment and tone. Claire Wild's spunky Despina is a delight and if Malin Bystrom's spectacularly aloof Fiordiligi is occasionally a little florid, she makes up for it with some peals of truly ferocious coloratura.

· Ends tonight. Box office: 0113 222 6222. Then touring.