Sunday night on “The Juke Joint” broadcast Robert Barclay previews the lineup for the 37th annual Chicago Blues Festival, the world’s largest free blues festival. This includes music by Shemekia Copeland, Toronzo Cannon, Billy Branch, Ronnie Baker Brooks, Thornetta Davis, Erwin Helfer, Cedric Burnside, Ivy Ford, Mr. Sipp, Eric Gales, Lurrie Bell and Johnny Rawls.