Good things come to those who wait, or so the old adage goes. For fans of musician Sid Selvidge, those are words to live by. These days, Selvidge is probably best known as the executive producer of the internationally syndicated radio show "Beale Street Caravan." But that's just one of the many lives he has led. Selvidge has a new album and will mark the release with a free concert Sunday at the Levitt Shell.