Mixing opera, electronica and folk genres, eccentric sister duo CocoRosie‘s fourth album, “Grey Oceans,” is undoubtedly strange, but musically complex and fascinating. With Celtic and Asian overtones, the song “Smokey Taboo” will invoke shivers. Employing acoustic and electronic sounds, the music creates contrasts between the desolate landscape of the desert and the interrupting “sirens in the street.” The playful honky-tonk piano on “Hopscotch”–the album’s most schizophrenic cut–gives way to a drum’n’bass-style beat that accompanies the eerie melody, and the emotional title track leaves Bianca Cassidy’s creepy, childlike vocals exposed, emphasized by guest pianist Gael Rakotondrabe’s gentle chords and Sierra Cassidy’s muted operatic soprano. The album’s duality is especially evident on the track “Lemonade,” which features melancholy piano over verses about death, juxtaposed with a cheerful pop chorus accompanied by warm vocal harmonies. Full of contradictions, the album is primitive and ultra-modern, dark and enchanting, tranquil and energetic.