The spiritual and the sensual find common cause in the music of Brandee Younger. As the world’s leading improvising harpist, she carries a torch for Alice Coltrane, whose astral meditations continue to light a path. But there’s also a place in Younger’s art for playfulness, even mischief — as she reminds us with Gadabout Season, her third album for Impulse! Records. Before a recent show at Solar Myth, part of Ars Nova Workshop’s 25th anniversary season, Younger sat down with The Late Set for this fun and far-ranging conversation. Weeks later, she’d be named a Doris Duke Artist and play Coltrane’s harp in a tribute at Carnegie Hall — making “New Pinnacle,” the title of a song on the new album, feel like a statement of fact.