Amadeus, Playhouse, Derby

With his productions of Sweeney Todd and A Midsummer Night's Dream, the director Stephen Edwards revealed the phenomenal depth of talent at Derby Playhouse. In their new Amadeus, this talented ensemble excels beyond belief. The production would disgrace neither the National nor the RSC, as it calls to mind that Wagnerian word, Gesamtkunstwerk - "total" theatre, the marriage of acting skill, technicals, music and direction that emulates Greek theatre.

When, amid Salieri's "mediocre" dying curses, Charles Balfour's lighting serves up a pendant Christ (Jay Reynolds), the whole stage colours like a Renaissance painting, a visual transformation from the subtle grey arches of the composer's idealistic, doomed initial pact with a boyhood Jesus. The colour mocks, ruthlessly.

Quality is the word for this stunning production, from the first groans of Julian Forsyth's antique composer, poised for his suicide attempt three decades after the premature demise of his mewling nemesis. "There was the Magic Flute, there beside me," he laments, eyeing Paul Ewing's quivering lips and salivating tongue amid "the stink of sweat and sausage" at the Schikaneder premiere. Sucking up to Joseph II (Christopher James, in the Jeffrey Jones role), seducing Constanze with "nipples of Venus" (brandied Roman chestnuts), spooning Lombardy mascarpone, or pursing and wincing as Ewing pre-empts "La ci darem" (Don Giovanni) and "batti, batti" with "The girl who doesn't love me can lick my arse", Forsyth plays his audience like the very squeeze-box to which he likens the magical bassoon and oboe-led opening of the "child's" B-flat Serenade.

Forsyth's tour de force is abetted by Maxine Fone and Philippa Waller as two hovering, feline "Venticelli", "my little wings", personifications of rumour omitted from the Forman-Shaffer film script: waspish news-bringers, cavorting Ariels, and Aeschylean Harpies-cum-Angels of Death and budding stars. They and the court seem ever-present in Rosie Alabaster's flexible library setting, deafly perusing while Salieri is the lurid voyeur. James's Joseph doesn't pastiche Milos Forman's film: those gorgeous lines, "Well, that's it, then," or, "Too many notes," have a buoyant tang. The court clones - Michael Kirk's strutting Orsini-Rosenberg, Robin Bowerman's van Swieten, Graeme Eton's von Strack - could yet hone their individual Viennese foibles further. The folding-in of the music by the sound-engineer Paul Delaney - Il Seraglio's coloratura, the double violin-viola concerto, Figaro Act by Act - is as superb as the evocative lighting changes, the seamless, sure, original direction, Kit Lane's subtle rear-projections (not a technical foot put wrong) and Jon Nicholls's finely understated linking score, with nasty mocking flute motif for the mischievously amplified whispering Harpies.

And then there was Ewing's Mozart - a surefire hit - paired with Katherine Manners's Constanze (their rows-reconciliations are worthy of Arthur Miller), and actually - like Salieri - playing the piano on stage, with staggering impact. The pouting, the pert little walk, the effortless shifting between languages, the vulgarity Salieri so loathes, it's all there. "It seemed to me that I had heard the voice of God, and it was the voice of an obscene child." Catch this brilliant obscenity if you can.

To 25 September (01332 363275)