Once again finding harmony and creating alchemy between seeming opposites, on Volta Björk is bold but thoughtful, delicate yet strong, accessible and avant. The intricacy and complexity of projects like Medúlla and Drawing Restraint 9 suggested that she might have left the more direct side of her work behind, but Volta's opening track and lead single, "Earth Intruders," puts that notion to rest: the song literally marches in, riding a bubbling, ritualistic beat courtesy of Timbaland and Konono No. 1's electric thumb-pianos. Björk howls "Turmoil! Carnage!" like incantations over the din, and after several albums' worth of beautiful whispers, it's a joy to hear her raise her voice and volume like this. "Wanderlust" follows and provides the yin to "Earth Intruders"' yang, its horns and brooding melody giving it the feel of a moodier, more contemplative version of "The Anchor Song." These two songs set the tone for the rest of Volta's pendulum-like swings between sounds and moods, all of which are tied together by found-sound and brass-driven interludes that give the impression that the album was recorded in a harbor -- an apt metaphor for how ideas and collaborators come and go on this album. Timbaland's beats resurface on "Innocence," another of Volta's most potent moments; a sample of what sounds like a man getting punched in the gut underscores Björk's viewpoint that purity is something powerful, not gentle. Antony and the Johnsons' Antony Hegarty lends his velvety voice to two outstanding but very different love songs: "The Dull Flame of Desire" captures swooning romance by pairing Björk and Hegarty's voices with a slowly building tattoo courtesy of Lightning Bolt drummer Brian Chippendale; "My Juvenile," which is dedicated to Björk's son Sindri, closes Volta with a much gentler duet. Considering how much sonic and emotional territory the album spans -- from the brash, anthemic "Declare Independence," which sounds a bit like Homogenic's "Pluto," to "Pneumonia" and "Vertebrae by Vertebrae," which are as elliptical and gentle as anything on Vespertine or Drawing Restraint 9 -- Volta could very easily sound scattered, but this isn't the case. Instead, it finds the perfect balance between the vibrancy of her poppier work in the '90s and her experiments in the 2000s.