Henry Street Chamber Opera produced a vibrant twin bill of Darius Milhaud’s Les Malheurs d’Orphée and Henry Purcell’s Dido and Aeneas . It was the second outing for this valuable, spunky group, whose purpose under its founder, the conductor Neal Goren, is to mine a repertoire that is unsuitable for the Met’s and the City Opera’s large auditoriums-small-scale, perhaps unfamiliar chamber operas that require relatively modest forces and flourish best in halls the size of Henry Street’s 375-seat jewel box of a theater. Both productions, which were directed by Laurence Dale, showed the virtue of minimal means. The Milhaud, a goofily haunting updating of the Orpheus myth set in the 1920′s, was done, appropriately, as a jaunty pop-up book. The Purcell production cleverly made the most of its monumental Dido, the opulent-voiced Camellia Johnson, by turning the Empress of Carthage into a totemic Easter Island–type goddess. But then the show lost its whimsical cool in displays of drag-show camp involving mincing witches and cavorting sailors. The full house, which included quite a few regulars from the big-league uptown venues, cheered the intrepid young singers and musicians as though we were all at the dawn of a bright new era, and-who knows?-maybe we were.