An opera based on a Russian silent film would seem the sort of artsy endeavor that invites dismissive sneers from musical and movie buffs alike. But with its lilting score and frank take on age-old questions, Bed and Sofa proved an enjoyable mixture of high-minded music and melodramatic fun. What's more, the latest offering from Boulder's Trouble Clef Theatre Company boasted three outstanding performances that bolstered the troupe's reputation as a premier presenter of musicals. Founded six years ago "to pursue new directions in musical theater," the group has taken on ambitious projects that, if not always polished to perfection, have been marked by their inventive staging, crisp musical direction and top-notch performances. It was altogether gratifying, then, to witness the company's years of hard work pay off in a production where art took precedence over personality and where every note, gesture and utterance felt right at home.