How do you follow up two Grammy-nominated records? If you're the North Mississippi Allstars, you don't necessarily adhere to critically-acclaimed formula like most bands would. Meaning don't expect the same hill-country gutbucket blooze that marked 2000's Shake Hands With Shorty and 2001's 51 Phantom.In a sense, the changes wrought on Polaris mirror those within the band itself; previously a trio, NMAS is now a quartet (R.L. Burnside's son Duwayne joined), and with Cody Dickinson writing songs alongside his older brother Luther, the overall framework is more democratic.More important, however, is the band's oft-stated intention not to be hemmed in by its audience's expectations. For every jamband community-friendly tune here-the good-timey, Southern rockin' "Eyes," the slide-guitar boogie of "Never in All My Days," the Grateful Dead-like "Conan"-there's a stylistic turnaround that suggests the Allstars ain't out to please nobody but themselves -Grammy voters included. And it's this damn-the-torpedoes attitude that helps make Polaris so fresh. Granted, a couple of the experiments aren't all that memorable; "Otay," with its synths, drum programming and hip-hop soul flavor, seems forced. But then you have tracks like the anthemic, unabashedly Beatle-esque "One to Grow On" (guest vocalist: Noel Gallagher) and psychedelic trance-rocker "All Along" (which, while nominally a blues, features a decidedly non-bluesy mellotron and a vibe that's more Pink Floyd than Pink Anderson). If they create a new Grammy category this year for "Most Diverse Album," put Polaris right at the top of the nominations list.