Folk and country have an especially powerful capacity to express sorrow. Catherine Irwin channels sadness in mellow Southern tones with the best of them on “Mockingbird,” off Little Heater (out September 18 via Thrill Jockey). While “Crying makes my head hurt” might sound trite elsewhere, Irwin sings it with an unassailable sincerity. From there on, the song displays an elegant sentimentality hard to find elsewhere. Download it below.