How and why this humble collection of towns hugging the Tennessee River in northern Alabama became a historic musical hot spot is an improbable, wonderful American story. But I grew interested in Muscle Shoals of today. More and more, roots and rock and roll musicians have been traveling there to record. A string of remarkable bands and songwriters, including Jason Isbell, John Paul White, St. Paul and the Broken Bones, Dylan LeBlanc and The Secret Sisters, has emerged from the area in recent years. A half dozen studios are in demand and busy. It’s became clear that Muscle Shoals is no museum. It’s a scene. So the only thing to do was to go there and listen.