Interesting that all three singers have "gravel" in their voices! As for Dylan, I listened to him in my early years when he was starting out and didn't think much of his voice but was wowed by his lyrics. Now I listen to his various incarnations and I marvel at his versatility. The fact is his voice has changed numerous times over the years -- sometimes sounding almost burned out -- but his lyrical ability and musical skill keep growing. Certainly one of the greats. Thanks for this article.