Teaming up for a second round with veteran rock producer John Leckie (the Stone Roses, XTC), British folk-pop ensemble Bellowhead continue to expand outward on their over-achieving fourth album Broadside. Their formula for (re)arranging traditional British and American folk songs into complex theatrical pop experiences seems to be ever-evolving as they dial up the energy and the intricacy on a fresh set of sea shanties, work ballads, and other obscure fare. Known as a powerhouse on-stage, the 11-piece band's dynamics come alive on disc as well, as they apply horns, harmonies, and clever time signatures to the Child Ballad chestnut "The Wife of Usher's Well" and the drinking/disaster ballad "The Old Dun Cow." Even their reading of the old Copper Family song, "Thousands or More," quickly goes prog after its lovely choral/accordion intro, morphing into a bustling display of embellished melodies and impressive musical chops. It's this showy enthusiasm and Bellowhead's unique vision that polarize listeners, but whether you prefer your folk music pure and earthy or massively messed with, it's tough to deny that they do what they do very well. Singer Jon Boden is a charismatic frontman, handling the often arcane material with ease and aplomb, and the band's harmonies are dazzling if occasionally a little too cleanly rendered. Those wanting to hear a few barnacles attached to their maritime songs should probably seek out the saltier style of Louis Killen, Paul Clayton, and other past masters. But straightforward renditions have never been Bellowhead's mission and even at their brightest and most ebullient, they understand the darkness and mystique in many of these songs, which are frequently underscored with challenging bits of dissonance and minor-key menace. In both the modern folk and pop realms, they are peerless in their passion, intensity, and sheer oddity.