Luther and Cody Dickinson are remarkable musicians, as anyone who has ever heard the guitarist and drummer can testify, and it’s to their credit that their long-running group The North Mississippi Allstars has never become a bluesy jam band, or something equally banal. Along with bassist Chris Chew, the band plays blues, sure, but they transcend the stereotypes by virtue of their ability to make something genuinely new — and truly musical — out of the down-home material they perform. Of course, Luther and Cody — the sons of late Memphis producer, pianist and all-around conceptualist Jim Dickinson — picked up a few neat tricks along the way, and they turned last year’s Keys to the Kingdom into a multilayered tribute to their father. From its Dylan cover to Big Star-flavored originals, Keys rocks and rolls. Live, they’re astounding — they’re true bluesmen, but that’s about half of it.