We’re about to talk to a person whose work is heard multiple times a day on WAMC — but rarely his voice. Until now. BJ Leiderman, the composer behind several public radio theme songs including those for Morning Edition, Marketplace, Wait Wait Don’t Tell Me, is out with his first album, called BJ. The album is both funny and serious, cheeky and earnest. And it even features Bela Fleck on banjo.