Improvisation Stephen Sondheim Awakens Fills Piano Bars with Tears and Melodies

It was decidedly louder at Duplex, which was an ad hoc reunion of “Mostly Sondheim,” an open mic that ended a 12-year run in 2016, across the street from Marie’s. Inside, musical theater insider jokes freely mixed with raunchy curses and references to “The Real Housewives of Salt Lake City.” Still, the gratitude room fell …