John Doyle, the British director who specializes in mounting musicals in which actors also play instruments, essentially whispers "Trust me" when the lights rise on his radical, magnificent, startlingly intelligent reimagining of this Stephen Sondheim-Hugh Wheeler musical. Those who recall Hal Prince's original (and colossal) 1979 Broadway production -- or Susan H. Schulman's revisited (and miniaturized) version 10 years later -- may find the conceit absurd. Mrs. Lovett plays tuba? Sweeney Todd strums guitar? Sweeney set in an insane asylum?

Oh, yes. Doyle's triumph -- one of several -- is that he has successfully reset the piece but hardly touched the text, one reason why Sondheim has embraced the production enthusiastically. Another triumph is the production's monochromatic (except for all the blood) palette. Doyle, doubling as the set designer, places everything on a 16-foot-wide platform, including nine chairs, a vertigo-inducing upstage-center shelving unit housing props, and a wooden coffin, black as pitch, set upon wooden horses and used to signify the location of scenes.

This allows the audience to focus on the intensely detailed performances. Remember Doyle's "Trust me"? We should. The sight of actors inhabiting characters and playing instruments is no more distracting than actors moving set pieces. Case closed.

His pallor ghastly, ghostly, Michael Cerveris is nonetheless a sexy Sweeney, his baritone offering a cascade of haunted sounds whether caressing his barber blades during "My Friends" or conveying Sweeney's psychological shakedown during "Epiphany," the song that presages Act II's fury-driven, bloodcurdling mayhem. Cerveris' physicality is used in fascinating ways: His Sweeney leaps from ladders when he sings; his Sweeney clutches the prop signifying his barber chair -- an infant's coffin, pure white -- his body taut as a steel trap.

There are few false moves in the supporting cast, even in an asylum where the real and unreal are interchangeable. Mark Jacoby's Judge Turpin is oddly attractive; you can imagine him bedding his ward, Johanna -- played neurotic yet adorable by Lauren Molina -- and her not minding. The cross-gender casting of Donna Lynne Champlin as Pirelli, Sweeney's tonsorial rival, pays off when the character's true identity is revealed. Alexander Gemignani's hilariously deadpan performance as Beadle cracks open the character's sycophancy, revealing the contemptuousness underneath. John Arbo's Jonas Fogg, Diana DiMarzio's Beggar Woman, and Manoel Felciano's Tobias are sturdy, but Felciano's "Not While I'm Around" is too earnest.

Patti LuPone, I predict, will win new converts with her performance. For one thing, she confronts the challenge of filling the shoes of her predecessors as Mrs. Lovett, starting with Angela Lansbury's brilliant slattern of 25 years ago and her own brassy take at an Avery Fisher Hall concert in 2000. Here she's anti-brass: Her first number, "The Worst Pies in London," conceived as sharp, sudden comic relief following all the grimace and gloom of Sweeney's exposition, is sung without bombast, LuPone crooning the tune in a subtle declaration of Sweeney lust that gives her Lovett a loving quality. With her hair cruelly bobbed, and black as that central coffin, there's a Felliniesque quality to this Sweeney that stuns and shimmers.