Colbie Caillat's voice exudes warmth on "Falling for You," an upbeat pop track that's hitting AC radio and just earned the singer her highest debut on the Billboard Hot 100 (No. 12). Rick Nowels, John Shanks and Ken Caillat (the singer's father) make up the song's production team, and the trio succeeds in giving Caillat's music a bit more of a bounce than was present on her debut album, "Coco." It also stays true to her signature sound. Like Caillat's breakthrough single, "Bubbly," the new song is about an emerging crush, and it's sweet and alluring. From its simple, feel-good lyrics and heavy guitar strum to the cheerful rhythm and hint of tambourine, "Falling for You" bodes well for Caillat's sophomore album, "Breakthrough," due Aug. 25.