Betty Carter brought speed, spontaneity, and precision to jazz singing, as in the dazzlingly abstract "Sounds (Movin' On)," but she was no less inventive when she took it slow. Carmen McRae, with whom Carter improvises with casual charm on "What's New," considered her the form's ne plus ultra, and the way Carter overdubs her pliable voice to bring out every nuance in "Sunday, Monday or Always" shows why.