TO ME, THERE are two kinds of guitar players,” Carlos Santana says. “Some people go up and down, or left and right, and some people go deeper in a different way by bending the strings. Because once you bend the strings, you’re messing with microtones. And microtones are the ones that give people chills. It brings tears to their eyes. There’s something about the sound of a microtone that reminds molecules to scream.