Crooked Still, the Boston-based band of neo-folk upstarts, defies generalization. Their instrumentation—fiddle, cello, banjo, bass, guitar and, at times, ukulele, glockenspiel, and piano—challenges listeners to pigeonhole them. And therein lies their brilliance.  Still Crooked, the band’s first release since its 2007 line up change (cellist/fiddler Tristan Claridge and fiddler Brittany Haas have joined founding members Aoife O’Donovan, Greg Liszt, and Corey DiMario after the departure of original cellist Rushad Eggleston) is magical. O’Donovan’s vocals are consistently haunting and hypnotic, perhaps best displayed by her maudlin prose during “Captain, Captain,” and the band’s virtuosic playing proves that it is enjoying the new energy born of its evolution from quartet to quintet. Still Crooked is astonishingly fresh, yet it resonates with a spirit centuries old.