Too many revivals of Stephen Sondheim's murderous 1979 musical masterpiece have suffered from something akin to the operatic mumps, a tendency to inflate its Grand Guignol vision with too much pomp and not enough circumstance. But director John Doyle triumphs here by taking precisely the opposite approach, stripping down the musical elements and sharpening the drama of this 2005 Broadway revival (based on his more modest English production) with a wicked twist: It's now a show-within-a-show staged by the inmates of a lunatic asylum. Doyle's Marat/Sade-flavored dramatic conceit is further enhanced by a minimalist musical approach that virtually does away with the orchestra, with the actors now providing their own instrumental accompaniment. While that gambit is often more effective on stage than in is in on a recording, here stars Michael Cerveris (a guitar-strumming Sweeney) and an Patti LuPone (who reprises Mrs. Lovett from a more traditionally operatic 2000 revival by the New York Philharmonic while improbably toting the tuba here) inform the renewed, intensely personal focus of the show's drama and songs with a deliciously dark charisma.