Chris Willman Senior Music Writer and Chief Music Critic For his new “Honeymind” album, singer and actor Ben Platt brought in an especially honeyed voice as a counterpart on one song, Brandy Clark. He had written “Treehouse” in a writing session with Clark well before the album was being put together, and then he and producer Dave Cobb had the eureka (or as Platt puts it, “duh”) moment of realizing just how much more haunting it might sound as a duet with the co-writer, whose chops obviously don’t begin and end with songwriting prowess.